Method of manufacturing magnetic head, and magnetic head sub-structure

ABSTRACT

A method of manufacturing magnetic heads comprises the step of: fabricating a magnetic head substructure by forming a plurality of components of the magnetic heads on a single substrate, wherein a plurality of rows of pre-head portions that will be the respective magnetic heads later are aligned in the substructure; and fabricating the magnetic heads by separating the pre-head portions from one another through cutting the substructure. In the step of fabricating the substructure, a plurality of indicators are formed, each of the indicators serving as a reference for indicating the location of a region ABS in which the medium facing surfaces of the magnetic heads are to be formed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of manufacturing magneticheads used for writing data on a recording medium and to a magnetic headsubstructure used for manufacturing magnetic heads.

2. Description of the Related Art

The recording systems of magnetic read/write devices include alongitudinal magnetic recording system wherein signals are magnetized inthe direction along the surface of the recording medium (thelongitudinal direction) and a perpendicular magnetic recording systemwherein signals are magnetized in the direction perpendicular to thesurface of the recording medium. It is known that the perpendicularmagnetic recording system is harder to be affected by thermalfluctuation of the recording medium and capable of implementing higherlinear recording density, compared with the longitudinal magneticrecording system.

In each of the longitudinal magnetic recording system and theperpendicular magnetic recording system, magnetic heads typically usedhave a structure in which a reproducing (read) head having amagnetoresistive element (that may be hereinafter called an MR element)for reading and a recording (write) head having an induction-typeelectromagnetic transducer for writing are stacked on a substrate.

In each of the longitudinal and perpendicular magnetic recordingsystems, the write head comprises a coil for generating a magnetic fieldcorresponding to data to be written on a recording medium, and amagnetic pole layer for allowing a magnetic flux corresponding to thefield generated by the coil to pass therethrough and generating a writemagnetic field for writing the data on the recording medium. The polelayer incorporates a track width defining portion and a wide portion,for example. The track width defining portion has an end located in amedium facing surface that faces toward the recording medium. The wideportion is coupled to the other end of the track width defining portionand has a width greater than the width of the track width definingportion. The track width defining portion has a nearly uniform width.

To achieve higher recording density, it is a reduction in track width,that is, a reduction in width of the end face of the pole layer taken inthe medium facing surface, and an improvement in writing characteristicsthat is required for the write head. An improvement in writingcharacteristics is, for example, an improvement in overwrite propertythat is a parameter indicating an overwriting capability. The overwriteproperty is reduced if the track width is reduced. It is thereforerequired to achieve a better overwrite property as the track width isreduced. Here, the length of the track width defining portion taken inthe direction orthogonal to the medium facing surface is called a neckheight. The smaller the neck height, the better is the overwriteproperty.

A magnetic head used for a magnetic disk drive such as a hard disk driveis typically provided in a slider. The slider has the above-mentionedmedium facing surface. The medium facing surface has an air-inflow-sideend and an air-outflow-side end. The slider slightly flies over thesurface of the recording medium by means of the airflow that comes fromthe air-inflow-side end into the space between the medium facing surfaceand the recording medium. The magnetic head is typically disposed nearthe air-outflow-side end of the medium facing surface of the slider. Ina magnetic disk drive the magnetic head is aligned through the use of arotary actuator, for example. In this case, the magnetic head moves overthe recording medium along a circular orbit centered on the center ofrotation of the rotary actuator. In such a magnetic disk drive, a tiltcalled a skew of the magnetic head is created with respect to thetangent of the circular track, in accordance with the position of themagnetic head across the tracks.

In a magnetic disk drive of the perpendicular magnetic recording systemthat exhibits a better capability of writing on a recording medium thanthe longitudinal magnetic recording system, in particular, if theabove-mentioned skew is created, there arise problems, such as aphenomenon in which data stored on an adjacent track is erased when datais written on a specific track (that is hereinafter called adjacenttrack erasing) or unwanted writing is performed between adjacent twotracks. To achieve higher recording density, it is required to suppressadjacent track erasing. Unwanted writing between adjacent two tracksaffects detection of servo signals for alignment of the magnetic headand the signal-to-noise ratio of a read signal.

A technique is known for preventing the problems resulting from the skewas described above, as disclosed in the Published U.S. PatentApplication No. 2003/0151850A1, the Published Unexamined Japanese PatentApplication 2003-203311, and the U.S. Pat. No. 6,504,675B1, for example.According to this technique, the end face of the track width definingportion located in the medium facing surface is made to have a shape inwhich the side located backward in the direction of travel of therecording medium (that is, the side located on the air-inflow-end sideof the slider) is shorter than the opposite side. Typically, in themedium facing surface of a magnetic head, the end farther from thesubstrate is located forward in the direction of travel of the recordingmedium (that is, on the air-outflow-end side of the slider). Therefore,the above-mentioned shape of the end face of the track width definingportion located in the medium facing surface is such that the sidecloser to the substrate is shorter than the side farther from thesubstrate.

As a magnetic head for the perpendicular magnetic recording system, amagnetic head comprising a pole layer and a shield is known, asdisclosed in the U.S. Pat. No. 4,656,546, for example. In the mediumfacing surface of this magnetic head, an end face of the shield islocated forward of an end face of the pole layer along the direction oftravel of the recording medium with a specific small space. Such amagnetic head will be hereinafter called a shield-type head. In theshield-type head, the shield prevents a magnetic flux from reaching therecording medium, the flux being generated from the end face of the polelayer and extending in directions except the direction perpendicular tothe surface of the recording medium. The shield-type head achieves afurther improvement in linear recording density.

The U.S. Pat. No. 4,672,493 discloses a magnetic head having a structurein which magnetic layers are provided forward and backward,respectively, in the direction of travel of the recording medium withrespect to a middle magnetic layer to be the pole layer, and coils aredisposed between the middle magnetic layer and the forward magneticlayer, and between the middle magnetic layer and the backward magneticlayer, respectively. This magnetic head is capable of increasingcomponents perpendicular to the surface of the recording medium amongcomponents of the magnetic field generated from themedium-facing-surface-side end of the middle magnetic layer.

Consideration will now be given to a method of forming a pole layer inwhich the end face of the track width defining portion located in themedium facing surface has a shape in which the side closer to thesubstrate is shorter than the side farther from the substrate, asmentioned above. In prior art, frame plating has been often employed asa method of forming such a pole layer. According to the method offorming the pole layer by frame plating, an electrode film is firstformed on a layer serving as a base of the pole layer. Next, aphotoresist layer is formed on the electrode film. The photoresist layeris then patterned to form a frame having a groove whose shapecorresponds to the pole layer. Next, plating is performed by feeding acurrent to the electrode film to form the pole layer in the groove. Theframe is then removed. Next, portions of the electrode film except theportion below the pole layer are removed.

When frame plating is employed, it is difficult to form a groove havinga small width in the photoresist layer by photolithography. Therefore,the problem is that it is difficult to reduce the track width when thepole layer is formed by frame plating. To solve this problem, it ispossible that, after forming the pole layer by frame plating, both sideportions of the track width defining portion are etched by dry etchingsuch as ion beam etching so as to reduce the track width.

In the course of manufacturing magnetic heads, a plurality of magnetichead elements to be the magnetic heads are formed in a single substrate(wafer). The substrate in which the magnetic head elements are formed iscut such that the surface to be the medium facing surfaces appears. Thissurface is then polished to form the medium facing surfaces.

FIG. 44 illustrates an example of shape of the top surface of the polelayer when the track width is reduced by etching both side portions ofthe track width defining portion as described above. FIG. 44 illustratesa neighborhood of the boundary between the track width defining portionindicated with numeral 201 and the wide portion indicated with numeral202. In FIG. 44, ‘ABS’ indicates a region in which the medium facingsurface is to be formed, ‘TW’ indicates the track width, and ‘NH’indicates the neck height as designed.

When the track width TW is reduced by etching the side portions of thetrack width defining portion 201, it is likely that the pole layer goesout of a desired shape. As a result, particularly when the neck heightNH is small, it is likely that the track width defining portion 201forms a shape in which the width varies depending on the location alongthe direction orthogonal to the medium facing surface (the verticaldirection in FIG. 44), as shown in FIG. 44.

When the track width defining portion 201 has a shape as shown in FIG.44, the neck height is strictly the length between the region ABS andthe point at which the width of the track width defining portion 201starts to be greater than the width thereof in the region ABS. However,if the neck height is thus defined, it is difficult to preciselydetermine the neck height when the track width defining portion 201 hasthe shape as shown in FIG. 44. Therefore, the neck height is defined aswill be described below when the track width defining portion 201 hasthe shape as shown in FIG. 44. In the top surface of the pole layer, animaginary line L1 passes through the intersection point of the regionABS and the side portion of the track width defining portion 201, andextends in the direction orthogonal to the region ABS. An imaginary lineL2 extends from a straight line portion of the side portion of the wideportion 202 connected to the side portion of the portion 201 and extendsin the direction in which the straight line portion extends. Theintersection point of the imaginary lines L1 and L2 is defined as C. Thedistance between the region ABS and the point C is defined as the neckheight. The neck height as thus defined is nearly equal to the neckheight NH as designed.

When the track width defining portion 201 has the shape as shown in FIG.44, it is impossible to obtain the track width TW in the course ofmanufacturing process of the magnetic heads unless the location of theregion ABS in which the medium facing surface is to be formed is known.In prior art, however, it is impossible to obtain a correct location ofthe region ABS in the course of manufacturing process of the magneticheads, and it is therefore impossible to obtain a correct track widthTW. Consequently, in prior art, even if the track width TW is out of adesired value in the course of manufacturing process of the magneticheads, it is impossible to recognize that until the head is completed,which results in a reduction in efficiency in manufacturing the magneticheads.

OBJECT AND SUMMARY OF THE INVENTION

It is an object of the invention to provide a method of manufacturingmagnetic heads and a magnetic head substructure for allowing the trackwidth to be obtained with accuracy in the course of manufacturingprocess of the magnetic heads.

Each of magnetic heads manufactured by the manufacturing method of theinvention comprises: a medium facing surface that faces toward arecording medium; a coil that generates a magnetic field correspondingto data to be written on the recording medium; and a pole layer thatincorporates a track width defining portion having an end face locatedin the medium facing surface, the pole layer allowing a magnetic fluxcorresponding to the field generated by the coil to pass therethroughand generating a write magnetic field for writing the data on therecording medium.

The method of manufacturing the magnetic heads of the inventioncomprises the steps of: fabricating a magnetic head substructure byforming a plurality of sets of the pole layer and the coil in asubstrate, wherein a plurality of rows of pre-head portions that will bethe respective magnetic heads later are aligned in the substructure; andfabricating the magnetic heads by separating the pre-head portions fromone another through cutting the substructure. The step of fabricatingthe substructure includes the step of forming a plurality of indicatorseach of which serves as a reference for indicating the location of aregion in which the medium facing surfaces of the magnetic heads are tobe formed.

According to the method of manufacturing the magnetic heads of theinvention, a plurality of indicators are formed in the step offabricating the substructure. Each of the indicators serves as areference for indicating the location of a region in which the mediumfacing surfaces of the magnetic heads are to be formed. As a result, inthe course of manufacturing process of the magnetic heads, it ispossible to obtain the location of the region in which the medium facingsurfaces are to be formed. It is thereby possible to obtain the trackwidth with accuracy.

In each of the magnetic heads manufactured by the method of theinvention, the end face of the track width defining portion located inthe medium facing surface may have: a first side close to the substrate;a second side located opposite to the first side; a third sideconnecting an end of the first side to an end of the second side; and afourth side connecting the other end of the first side to the other endof the second side. In addition, the second side may define the trackwidth, and the end face of the track width defining portion may have awidth that decreases as the distance from the first side decreases.

In the method of the invention, the indicators may be formed on bothsides of the track width defining portion, the sides being opposed toeach other in a direction of width of the defining portion, in the stepof forming the indicators. In this case, in the substructure, each ofthe pole layers and the indicators may be conductive, and the indicatorsmay be electrically connected to the respective pole layers.

In the method of the invention, the step of fabricating the substructuremay further include the step of forming an encasing layer having groovesthat accommodate the pole layers, and the pole layers may be disposed inthe grooves of the encasing layer. In this case, in the step of formingthe indicators, the indicators may be formed of a layer located at aheight the same as the height at which the pole layers are located.

In the method of the invention, the step of fabricating the substructuremay further include the step of forming a magnetic layer having portionsthat will be the pole layers, and the indicators may be made up of otherportions of the magnetic layer. In this case, the step of fabricatingthe substructure may further include the step of forming an encasinglayer having a groove that accommodates the magnetic layer, and themagnetic layer may be disposed in the groove of the encasing layer.

In the method of the invention, the step of fabricating the substructuremay further include the step of forming a magnetic layer having portionsthat will be the pole layers, and the indicators may be made up of alayer other than the magnetic layer. In this case, the step offabricating the substructure may further include the step of forming anencasing layer having a first groove that accommodates the magneticlayer and second grooves that accommodate the indicators, the magneticlayer may be formed in the first groove of the encasing layer, and theindicators may be formed in the second grooves.

In the method of the invention, the indicators may be formed of a layerlocated closer to the substrate than the pole layers in the step offorming the indicators.

In the method of the invention, the indicators may be formed of a layerhaving conductivity.

In the method of the invention, the step of fabricating the substructuremay further include the step of forming an encasing layer having groovesthat accommodate the pole layers and other grooves that form theindicators.

In the method of the invention, each of the indicators may have an endthat is parallel to the region in which the medium facing surfaces areto be formed, and the location of the end may serve as a reference forindicating the location of the region. In this case, the distancebetween the location of the reference and the region may fall within arange of 0 to 1.0 μm inclusive.

In the method of the invention, each of the indicators may have two endsthat are parallel to the region in which the medium facing surfaces areto be formed, and the location of the middle between the two ends mayserve as a reference for indicating the location of the region. In thiscase, the distance between the location of the reference and the regionmay fall within a range of 0 to 1.0 μm inclusive.

In the method of the invention, in the substructure, the distancebetween the track width defining portion and the indicators taken in thedirection of width of the defining portion may fall within a range of0.1 to 5.0 μm inclusive.

In the method of the invention, the indicators may be located in aregion that will not remain in the magnetic heads.

In the method of the invention, at least part of each of the indicatorsmay be located in a region that will remain in the magnetic heads. Inthis case, the part of each of the indicators that remains in themagnetic heads may indicate the length of the track width definingportion taken in the direction orthogonal to the medium facing surface.The method of manufacturing the magnetic heads may further comprise thestep of measuring the length of the track width defining portion takenin the direction orthogonal to the medium facing surface by measuringthe length of the part of each of the indicators that remains in themagnetic heads taken in the direction orthogonal to the medium facingsurface, the step being performed after the step of fabricating themagnetic heads.

In the method of the invention, the step of fabricating the magneticheads may include the step of forming the medium facing surfaces bypolishing a surface formed by cutting the substructure.

In the method of the invention, the magnetic heads may be those used fora perpendicular magnetic recording system.

A magnetic head substructure of the invention are used for manufacturingmagnetic heads. Each of the magnetic heads comprises: a medium facingsurface that faces toward a recording medium; a coil that generates amagnetic field corresponding to data to be written on the recordingmedium; and a pole layer that incorporates a track width definingportion having an end face located in the medium facing surface, thepole layer allowing a magnetic flux corresponding to the field generatedby the coil to pass therethrough and generating a write magnetic fieldfor writing the data on the recording medium.

The substructure of the invention comprises: a substrate; a plurality ofsets of the pole layer and the coil formed in the substrate such that aplurality of rows of pre-head portions that will be the respectivemagnetic heads later are aligned; and a plurality of indicators each ofwhich serves as a reference for indicating a region in which the mediumfacing surfaces of the magnetic heads are to be formed.

The substructure of the invention includes a plurality of indicatorseach of which serves as a reference for indicating the location of aregion in which the medium facing surfaces of the magnetic heads are tobe formed. As a result, in the course of manufacturing process of themagnetic heads, it is possible to obtain the location of the region inwhich the medium facing surfaces are to be formed. It is therebypossible to obtain the track width with accuracy.

In each of the magnetic heads manufactured through the use of thesubstructure of the invention, the end face of the track width definingportion located in the medium facing surface may have: a first sideclose to the substrate; a second side located opposite to the firstside; a third side connecting an end of the first side to an end of thesecond side; and a fourth side connecting the other end of the firstside to the other end of the second side. In addition, the second sidemay define the track width, and the end face of the track width definingportion may have a width that decreases as the distance from the firstside decreases.

In the substructure of the invention, the indicators may be provided onboth sides of the track width defining portion, the sides being opposedto each other in a direction of width of the defining portion. In thiscase, each of the pole layers and the indicators may be conductive, andthe indicators may be electrically connected to the respective polelayers.

The substructure of the invention may further comprise an encasing layerhaving grooves that accommodate the pole layers. In this case, theindicators may be made of a layer located at a height the same as theheight at which the pole layers are located.

The substructure of the invention may further comprise a magnetic layerhaving portions that will be the pole layers, and the indicators may bemade up of other portions of the magnetic layer. In this case, thesubstructure may further comprise an encasing layer having a groove thataccommodates the magnetic layer.

The substructure of the invention may further comprise a magnetic layerhaving portions that will be the pole layers, wherein the indicators aremade up of a layer other than the magnetic layer. In this case, thesubstructure may further comprise an encasing layer having a firstgroove that accommodates the magnetic layer and second grooves thataccommodate the indicators.

In the substructure of the invention, the indicators may be made of alayer located closer to the substrate than the pole layers.

In the substructure of the invention, the indicators may be made of alayer having conductivity.

The substructure of the invention may further comprise an encasing layerhaving grooves that accommodate the pole layers and other grooves thatform the indicators.

In the substructure of the invention, each of the indicators may have anend that is parallel to the region in which the medium facing surfacesare to be formed, and the location of the end may serve as a referencefor indicating the location of the region. In this case, the distancebetween the location of the reference and the region may fall within arange of 0 to 1.0 μm inclusive.

In the substructure of the invention, each of the indicators may havetwo ends that are parallel to the region in which the medium facingsurfaces are to be formed, and the location of the middle between thetwo ends may serve as a reference for indicating the location of theregion. In this case, the distance between the location of the referenceand the region may fall within a range of 0 to 1.0 μm inclusive.

In the substructure of the invention, the distance between the trackwidth defining portion and the indicators taken in the direction ofwidth of the defining portion may fall within a range of 0.1 to 5.0 μminclusive.

In the substructure of the invention, the indicators may be located in aregion that will not remain in the magnetic heads.

In the substructure of the invention, at least part of each of theindicators may be located in a region that will remain in the magneticheads. In this case, the part of each of the indicators that remains inthe magnetic heads may indicate the length of the track width definingportion taken in the direction orthogonal to the medium facing surface.

In the substructure of the invention, the magnetic heads may be thoseused for the perpendicular magnetic recording system.

According to the method of manufacturing the magnetic heads of theinvention, in the step of fabricating the substructure, a plurality ofindicators are formed each of which serves as the reference forindicating the location of the region in which the medium facingsurfaces of the magnetic heads are to be formed. As a result, accordingto the invention, it is possible to obtain the location of the region inwhich the medium facing surfaces are to be formed, in the course ofmanufacturing process of the magnetic heads. It is thereby possible toobtain the track width with accuracy.

The magnetic head substructure of the invention includes a plurality ofindicators each of which serves as the reference for indicating thelocation of the region in which the medium facing surfaces of themagnetic heads are to be formed. As a result, according to theinvention, it is possible to obtain the location of the region in whichthe medium facing surfaces are to be formed, in the course ofmanufacturing process of the magnetic heads. It is thereby possible toobtain the track width with accuracy.

In each of the magnetic heads manufactured by the method of theinvention or manufactured through the use of the substructure of theinvention, the end face of the track width defining portion located inthe medium facing surface may have: a first side close to the substrate;a second side located opposite to the first side; a third sideconnecting an end of the first side to an end of the second side; and afourth side connecting the other end of the first side to the other endof the second side. In addition, the second side may define the trackwidth, and the end face of the track width defining portion may have awidth that decreases as the distance from the first side decreases. Inthis case, it is possible to prevent the problems resulting from theskew.

In the method of the invention or the substructure of the invention, theindicators may be provided on both sides of the track width definingportion, the sides being opposed to each other in the direction of widthof the defining portion. In this case, it is possible to obtain thelocation of the region in which the medium facing surfaces are to beformed with higher accuracy, using the two indicators provided on bothsides of the track width defining portion as the reference.

In the method of the invention or the substructure of the invention,each of the pole layers and the two indicators provided on both sides ofthe track width defining portion opposed to each other in the directionof width of the defining portion may be conductive, and the indicatorsmay be electrically connected to the respective pole layers. In thiscase, when the indicators are observed by an electron microscope, it ispossible to prevent electric charges from accumulating on theindicators. It is thereby possible to obtain correct images of theindicators. It is thereby possible to obtain the location of the regionin which the medium facing surfaces are to be formed with higheraccuracy.

In the method of the invention or the substructure of the invention, thepart of each of the indicators that remains in the magnetic heads mayindicate the length of the track width defining portion taken in thedirection orthogonal to the medium facing surface. In this case, afterthe magnetic heads are completed, it is possible to measure the lengthof the track width defining portion taken in the direction orthogonal tothe medium facing surface by measuring the length of the part of each ofthe indicators that remains in the magnetic heads taken in the directionorthogonal to the medium facing surface.

Other and further objects, features and advantages of the invention willappear more fully from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates indicator portions of a first embodiment of theinvention.

FIG. 2 is a front view of the medium facing surface of a magnetic headof the first embodiment of the invention.

FIG. 3 is a cross-sectional view for illustrating the configuration ofthe magnetic head of the first embodiment of the invention.

FIG. 4 is a top view of the pole layer of the magnetic head of the firstembodiment of the invention.

FIG. 5A and FIG. 5B are views for illustrating a step of a method ofmanufacturing the magnetic head of the first embodiment of theinvention.

FIG. 6A and FIG. 6B are views for illustrating the main part of FIG. 5Aand FIG. 5B.

FIG. 7A and FIG. 7B are views for illustrating a step that follows thestep shown in FIG. 5A and FIG. 5B.

FIG. 8A and FIG. 8B are views for illustrating the main part of FIG. 7Aand FIG. 7B.

FIG. 9A and FIG. 9B are views for illustrating a step that follows thestep shown in FIG. 7A and FIG. 7B.

FIG. 10A and FIG. 10B are views for illustrating the main part of FIG.9A and FIG. 9B.

FIG. 11A and FIG. 11B are views for illustrating a step that follows thestep shown in FIG. 9A and FIG. 9B.

FIG. 12A and FIG. 12B are views for illustrating the main part of FIG.11A and FIG. 11B.

FIG. 13A and FIG. 13B are views for illustrating a step that follows thestep shown in FIG. 11A and FIG. 11B.

FIG. 14A and FIG. 14B are views for illustrating a step that follows thestep shown in FIG. 13A and FIG. 13B.

FIG. 15A and FIG. 15B are views for illustrating a step that follows thestep shown in FIG. 14A and FIG. 14B.

FIG. 16A and FIG. 16B are views for illustrating a step that follows thestep shown in FIG. 15A and FIG. 15B.

FIG. 17 is a top view of a magnetic head substructure of the firstembodiment of the invention.

FIG. 18 is a perspective view for schematically illustrating theconfiguration of a lapping apparatus used in the method of manufacturingthe magnetic head of the first embodiment of the invention.

FIG. 19 is a block diagram illustrating an example of circuitconfiguration of the lapping apparatus of FIG. 18.

FIG. 20A and FIG. 20B are views for illustrating a modification exampleof the method of manufacturing the magnetic head of the first embodimentof the invention.

FIG. 21 illustrates indicator portions of a second embodiment of theinvention.

FIG. 22 illustrates an example of arrangement of indicator portions of athird embodiment of the invention.

FIG. 23 illustrates another example of arrangement of the indicatorportions of the third embodiment of the invention.

FIG. 24 illustrates indicator portions of a fourth embodiment of theinvention.

FIG. 25A and FIG. 25B are views for illustrating a step of a method ofmanufacturing a magnetic head of a fifth embodiment of the invention.

FIG. 26A and FIG. 26B are views for illustrating the main part of FIG.25A and FIG. 25B.

FIG. 27A and FIG. 27B are views for illustrating a step that follows thestep shown in FIG. 25A and FIG. 25B.

FIG. 28A and FIG. 28B are views for illustrating the main part of FIG.27A and FIG. 27B.

FIG. 29A and FIG. 29B are views for illustrating a step that follows thestep shown in FIG. 27A and FIG. 27B.

FIG. 30A and FIG. 30B are views for illustrating a step that follows thestep shown in FIG. 29A and FIG. 29B.

FIG. 31A and FIG. 31B are views for illustrating a step that follows thestep shown in FIG. 29A and FIG. 29B.

FIG. 32A and FIG. 32B are views for illustrating a step that follows thestep shown in FIG. 31A and FIG. 31B.

FIG. 33A and FIG. 33B are views for illustrating a step that follows thestep shown in FIG. 32A and FIG. 32B.

FIG. 34 illustrates indicator portions of a sixth embodiment of theinvention.

FIG. 35A and FIG. 35B are views for illustrating a step of a method ofmanufacturing a magnetic head of the sixth embodiment of the invention.

FIG. 36A and FIG. 36B are views for illustrating a step that follows thestep shown in FIG. 35A and FIG. 35B.

FIG. 37A and FIG. 37B are views for illustrating a step that follows thestep shown in FIG. 36A and FIG. 36B.

FIG. 38A and FIG. 38B are views for illustrating a step that follows thestep shown in FIG. 37A and FIG. 37B.

FIG. 39A and FIG. 39B are views for illustrating a step that follows thestep shown in FIG. 38A and FIG. 38B.

FIG. 40A and FIG. 40B are views for illustrating a step that follows thestep shown in FIG. 39A and FIG. 39B.

FIG. 41A and FIG. 41B are views for illustrating a step that follows thestep shown in FIG. 40A and FIG. 40B.

FIG. 42A and FIG. 42B are views for illustrating a step that follows thestep shown in FIG. 41A and FIG. 41B.

FIG. 43A and FIG. 43B are views for illustrating a step that follows thestep shown in FIG. 42A and FIG. 42B.

FIG. 44 is a view for illustrating an example of shape of a pole layer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

Preferred embodiments of the invention will now be described in detailwith reference to the accompanying drawings. Reference is now made toFIG. 2 and FIG. 3 to describe a manufacturing method and theconfiguration of a magnetic head manufactured through the use of amagnetic head substructure of a first embodiment of the invention. Here,a magnetic head for the perpendicular magnetic recording system will bedescribed as an example of the magnetic head. FIG. 2 is a front view forillustrating the medium facing surface of the magnetic head of theembodiment. FIG. 3 is a cross-sectional view for illustrating theconfiguration of the magnetic head of the embodiment. FIG. 3 illustratesa cross section orthogonal to the medium facing surface and a surface ofa substrate. The arrow indicated with T in FIG. 3 shows the direction oftravel of a recording medium.

As shown in FIG. 2 and FIG. 3, the magnetic head of the embodimentcomprises: a substrate 1 made of a ceramic such as aluminum oxide andtitanium carbide (Al₂O₃—TiC); an insulating layer 2 made of aninsulating material such as alumina (Al₂O₃) and disposed on thesubstrate 1; a bottom shield layer 3 made of a magnetic material anddisposed on the insulating layer 2; a bottom shield gap film 4 that isan insulating film disposed on the bottom shield layer 3; amagnetoresistive (MR) element 5 as a read element disposed on the bottomshield gap film 4; a top shield gap film 6 that is an insulating filmdisposed on the MR element 5; and a top shield layer 7 made of amagnetic material and disposed on the top shield gap film 6. The portionfrom the bottom shield layer 3 to the top shield layer 7 make up theread head.

The MR element 5 has an end that is located in the medium facing surface30 that faces toward a recording medium. The MR element 5 may be anelement made of a magneto-sensitive film that exhibits amagnetoresistive effect, such as an anisotropic magnetoresistive (AMR)element, a giant magnetoresistive (GMR) element, or a tunnelmagnetoresistive (TMR) element.

The magnetic head further comprises: an insulating layer 8 made of aninsulating material and disposed on the top shield layer 7; a coil 9formed on the insulating layer 8; an insulating layer 10 made of aninsulating material and disposed around the coil 9 and in the spacebetween adjacent ones of the turns of the coil 9; and an insulatinglayer 11 made of an insulating material and disposed around theinsulating layer 10. The coil 9 is flat-whorl-shaped. The coil 9 and theinsulating layers 10 and 11 have flattened top surfaces. The insulatinglayers 8 and 11 are made of alumina, for example. The insulating layer10 is made of photoresist, for example. The coil 9 is made of aconductive material such as copper.

The magnetic head further comprises an encasing layer 12 made of anonmagnetic material and disposed on the flattened top surfaces of thecoil 9 and the insulating layers 10 and 11. The encasing layer 12 has agroove 120 that opens in the top surface thereof and that accommodatesthe pole layer described later. Although the groove 120 does notpenetrate the encasing layer 12 in FIG. 2 and FIG. 3, the groove 120 maypenetrate the encasing layer 12. The encasing layer 12 may be made ofany of alumina, silicon oxide (SiO_(x)), and silicon oxynitride (SiON),for example.

The magnetic head further comprises a polishing stopper layer 13 made ofa nonmagnetic conductive material and disposed on the top surface of theencasing layer 12. The polishing stopper layer 13 has an opening 13 athat penetrates, and the edge of the opening 13 a is located directlyabove the edge of the groove 120 in the top surface of the encasinglayer 12. The polishing stopper layer 13 may be made of any of Ta, Mo,W, Ti, Ru, Rh, Re, Pt, Pd, Ir, TiN, TiW and NiCr, for example.

The magnetic head further comprises the pole layer 16 disposed in thegroove 120. The pole layer 16 incorporates: a first layer 161 locatedcloser to the surface of the groove 120; and a second layer 162 locatedfarther from the surface of the groove 120. The polishing stopper layer13 and the pole layer 16 have flattened top surfaces.

Each of the first layer 161 and the second layer 162 is made of amagnetic material. The first layer 161 may be made of any of CoFeN,CoNiFe and NiFe, for example. The second layer 162 may be made of any ofNiFe, CoNiFe and CoFe, for example.

The magnetic head further comprises a gap layer 18 disposed on theflattened top surfaces of the polishing stopper layer 13 and the polelayer 16. The gap layer 18 has an opening located at a distance from themedium facing surface 30. The gap layer 18 may be made of an insulatingmaterial such as alumina or a nonmagnetic metal material such as Ru,NiCu, Ta, W or NiB.

The magnetic head further comprises a shield layer 20. The shield layer20 has: a first layer 20A disposed on the gap layer 18; a second layer20C disposed on the first layer 20A; a yoke layer 20B disposed on aportion of the pole layer 16 where the opening of the gap layer 18 isformed; a coupling layer 20D disposed on the yoke layer 20B; and a thirdlayer 20E disposed to couple the second layer 20C to the coupling layer20D. The first layer 20A, the yoke layer 20B, the second layer 20C, thecoupling layer 20D and the third layer 20E are each made of a magneticmaterial. These layers 20A to 20E may be made of any of CoFeN, CoNiFeand NiFe, for example.

The magnetic head further comprises a nonmagnetic layer 21 made of anonmagnetic material and disposed around the yoke layer 20B. A portionof the nonmagnetic layer 21 is disposed on a side of the first layer20A. The nonmagnetic layer 21 is made of an inorganic insulatingmaterial such as alumina or coating glass. Alternatively, thenonmagnetic layer 21 may be made up of a layer of a nonmagnetic metalmaterial and a layer of an insulating material disposed thereon. In thiscase, the nonmagnetic metal material may be a refractory metal such asTa, Mo, Nb, W, Cr, Ru, Cu or Ni.

The magnetic head further comprises: an insulating layer 22 disposed onregions of the top surfaces of the yoke layer 20B and the nonmagneticlayer 21 in which a coil described later is disposed; the coil 23disposed on the insulating layer 22; an insulating layer 24 disposedaround the coil 23 and in the space between adjacent ones of the turnsof the coil 23; and an insulating layer 25 disposed on the coil 23 andthe insulating layer 24. The coil 23 is flat-whorl-shaped. A portion ofthe coil 23 passes between the second layer 20C and the coupling layer20D. The coil 23 is made of a conductive material such as copper. Thesecond layer 20C, the coupling layer 20D, the coil 23 and the insulatinglayer 24 have flattened top surfaces. The insulating layer 24 is made ofphotoresist, for example. The insulating layers 22 and 25 are made ofalumina, for example.

The portion from the coil 9 to the third layer 20E of the shield layer20 make up the write head. Although not shown, the magnetic head furthercomprises a protection layer for covering the shield layer 20.

As described so far, the magnetic head of the embodiment comprises themedium facing surface 30 that faces toward a recording medium, the readhead, and the write head. The read head and the write head are stackedon the substrate 1. The read head is disposed backward in the directionT of travel of the recording medium (that is, on the air-inflow-end sideof the slider). The write head is disposed forward in the direction T oftravel of the recording medium (that is, on the air-outflow-end side ofthe slider).

The read head comprises the MR element 5 as the read element, and thebottom shield layer 3 and the top shield layer 7 for shielding the MRelement 5. Portions of the bottom shield layer 3 and the top shieldlayer 7 that are located on a side of the medium facing surface 30 areopposed to each other, the MR element 5 being placed between theseportions. The read head further comprises: the bottom shield gap film 4disposed between the MR element 5 and the bottom shield layer 3; and thetop shield gap film 6 disposed between the MR element 5 and the topshield layer 7.

The write head comprises the coil 9, the encasing layer 12, thepolishing stopper layer 13, the pole layer 16, the gap layer 18, theshield layer 20, and the coil 23. The coils 9 and 23 generate a magneticfield corresponding to data to be written on the recording medium. Thecoil 9 is not a component requisite for the write head and may beomitted.

The pole layer 16 has an end face located in the medium facing surface30. The pole layer 16 allows the magnetic flux corresponding to thefield generated by the coil 23 to pass therethrough and generates awrite magnetic field for writing the data on the medium by using theperpendicular magnetic recording system.

The shield layer 20 has an end located in the medium facing surface 30,and has a portion located away from the medium facing surface 30 andcoupled to the pole layer 16. The gap layer 18 is made of a nonmagneticmaterial and provided between the pole layer 16 and the shield layer 20.

In the medium facing surface 30, the end face of the shield layer 20 isdisposed forward of the end face of the track width defining portion 16Aalong the direction T of travel of the recording medium with a specificspace created by the thickness of the gap layer 18. At least part of thecoil 23 is disposed between the pole layer 16 and the shield layer 20and insulated from the pole layer 16 and the shield layer 20.

The shield layer 20 has: the first layer 20A disposed adjacent to thegap layer 18; the second layer 20C disposed on a side of the first layer20A farther from the gap layer 18; the yoke layer 20B disposed on theportion of the pole layer 16 where the opening of the gap layer 18 isformed; the coupling layer 20D disposed on the yoke layer 20B; and thethird layer 20E disposed to couple the second layer 20C to the couplinglayer 20D. The second layer 20C is disposed between the medium facingsurface 30 and the at least part of the coil 23.

FIG. 4 is a top view of the pole layer 16. As shown in FIG. 4, the polelayer 16 incorporates the track width defining portion 16A and a wideportion 16B. The track width defining portion 16A has an end located inthe medium facing surface 30 and has a uniform width. The wide portion16B is coupled to the other end of the track width defining portion 16Aand has a width greater than the width of the track width definingportion 16A. The wide portion 16B is equal in width to the track widthdefining portion 16A at the interface with the track width definingportion 16A, and gradually increases in width as the distance from themedium facing surface 30 increases and then maintains a specific widthto the end of the wide portion 16B. Here, the length of the track widthdefining portion 16A taken in the direction orthogonal to the mediumfacing surface 30 is called a neck height NH. The neck height NH fallswithin a range of 0.1 to 0.3 μm inclusive, for example.

As shown in FIG. 2, the end face of the track width defining portion 16Alocated in the medium facing surface 30 has: a first side A1 close tothe substrate 1; a second side A2 opposite to the first side A1; a thirdside A3 connecting an end of the first side A1 to an end of the secondside A2; and a fourth side A4 connecting the other end of the first sideA1 to the other end of the second side A2. The second side A2 definesthe track width. The width of the end face of the track width definingportion 16A located in the medium facing surface 30 decreases as thedistance from the first side A1 decreases.

The length of the second side A2, that is, the track width, falls withina range of 0.08 to 0.12 μm inclusive, for example. The thickness of thepole layer 16 falls within a range of 0.20 to 0.30 μm inclusive, forexample. Each of the third side A3 and the fourth side A4 forms an anglethat falls within a range of 5 to 12 degrees inclusive, for example,with respect to the direction orthogonal to the top surface of thesubstrate 1. The thickness of the gap layer 18 falls within a range of30 to 60 nm inclusive, for example.

The polishing stopper layer 13 is disposed on the top surface of theencasing layer 12. The polishing stopper layer 13 has the opening 13 athat penetrates, and the edge of the opening 13 a is located directlyabove the edge of the groove 120 in the top surface of the encasinglayer 12. The polishing stopper layer 13 has a thickness that fallswithin a range of 20 to 60 nm inclusive, for example.

The pole layer 16 incorporates: the first layer 161 located closer tothe surface of the groove 120; and the second layer 162 located fartherfrom the surface of the groove 120. The first layer 161 has a thicknessthat falls within a range of 40 to 100 nm inclusive, for example.

The first layer 20A of the shield layer 20 has: a first end located inthe medium facing surface 30; and a second end opposite to the firstend. The second layer 20C of the shield layer 20 also has: a first endlocated in the medium facing surface 30; and a second end opposite tothe first end. The second end of the first layer 20A defines the throatheight TH. That is, as shown in FIG. 3, the throat height TH is theminimum distance between the first end and the second end of the portionof the first layer 20A facing toward the pole layer 16 with the gaplayer 18 disposed in between. The throat height TH falls within a rangeof 0.1 to 0.3 μm inclusive, for example. The minimum distance betweenthe first end and the second end of the portion of the second layer 20Cfacing toward the pole layer 16 with the gap layer 18 and the firstlayer 20A disposed in between falls within a range of 0.5 to 0.8 μminclusive, for example. The first layer 20A and the yoke layer 20B havea thickness that falls within a range of 0.3 to 0.8 μm inclusive, forexample. The second layer 20C and the coupling layer 20D have athickness that falls within a range of 2.0 to 2.5 μm inclusive, forexample. The third layer 20E has a thickness that falls within a rangeof 2.0 to 3.0 μm inclusive, for example. The coil 23 has a thicknessthat is equal to or smaller than the thickness of the second layer 20Cand that falls within a range of 2.0 to 2.5 μm inclusive, for example.

In the drawings of the present patent application such as FIG. 3, thepole layer 16 is shown greater in thickness than the yoke layer 20B toillustrate details of the structure around the pole layer 16. However,the pole layer 16 actually has a thickness that is nearly equal to orsmaller than the thickness of the yoke layer 20B, for example.

The magnetic head of the embodiment writes data on a recording medium byusing the write head and reads data written on the recording medium byusing the read head. In the write head, the coil 23 generates a magneticfield that corresponds to the data to be written on the medium. The polelayer 16 and the shield layer 20 form a magnetic path through which amagnetic flux corresponding to the magnetic field generated by the coil23 passes. The pole layer 16 allows the flux corresponding to the fieldgenerated by the coil 23 to pass and generates a write magnetic fieldused for writing the data on the medium through the use of theperpendicular magnetic recording system. The shield layer 20 takes in adisturbance magnetic field applied from outside the magnetic head to themagnetic head. It is thereby possible to prevent erroneous writing onthe recording medium caused by the disturbance magnetic fieldintensively taken in into the pole layer 16.

According to the embodiment, in the medium facing surface 30, the endface of the shield layer 20 is disposed forward of the end face of thetrack width defining portion 16A along the direction T of travel of therecording medium (that is, on the air-outflow-end side of the slider)with a specific small space created by the gap layer 18. The location ofan end of the bit pattern written on the recording medium is determinedby the location of the end of the pole layer 16 that is closer to thegap layer 18 and located in the medium facing surface 30. The shieldlayer 20 takes in a magnetic flux generated from the end face of thepole layer 16 located in the medium facing surface 30 and extending indirections except the direction orthogonal to the surface of therecording medium so as to prevent the flux from reaching the recordingmedium. It is thereby possible to prevent the direction of magnetizationof the bit pattern already written on the medium from being changed dueto the effect of the above-mentioned flux. According to the embodiment,an improvement in linear recording density is thus achieved.

According to the embodiment, as shown in FIG. 2, the end face of thetrack width defining portion 16A located in the medium facing surface 30has a width that decreases as the distance from the first side A1decreases. It is thereby possible to prevent the problems resulting fromthe skew.

Reference is now made to FIG. 5A to FIG. 16A, and FIG. 5B to FIG. 16B todescribe a method of manufacturing the magnetic head of the embodimentand a magnetic head substructure of the embodiment. The method ofmanufacturing the magnetic head of the embodiment comprises the steps offabricating the magnetic head substructure in which a plurality of rowsof pre-head portions to be the magnetic heads are aligned by formingcomponents of a plurality of magnetic heads in a single substrate; andfabricating the magnetic heads by separating the pre-head portionsthrough cutting the magnetic head substructure. One of the pre-headportions will now be described. Portions closer to the substrate 1 thanthe encasing layer 12 are omitted in FIG. 5A to FIG. 16A, and FIG. 5B toFIG. 16B. ‘ABS’ indicates a region in which the medium facing surface isto be formed.

According to the method of manufacturing the magnetic head of theembodiment, as shown in FIG. 3, the insulating layer 2, the bottomshield layer 3 and the bottom shield gap film 4 are first formed on thesubstrate 1 one by one. Next, the MR element 5 and a lead not shown thatis connected to the MR element 5 are formed on the bottom shield gapfilm 4. Next, the MR element 5 and the lead are covered with the topshield gap film 6. Next, the top shield layer 7 and the insulating layer8 are formed one by one on the top shield gap film 6. Next, the coil 9and the insulating layers 10 and 11 are formed on the insulating layer8. Next, the top surfaces of the coil 9 and the insulating layers 10 and11 are flattened by chemical mechanical polishing (hereinafter referredto as CMP), for example.

FIG. 5A, FIG. 5B, FIG. 6A and FIG. 6B illustrate the following step.FIG. 5A shows the top surface of the layered structure obtained in thecourse of manufacturing process of the magnetic head. FIG. 5B shows across section of the layered structure orthogonal to the medium facingsurface and the substrate. FIG. 5B is a cross section taken along lineB-B of FIG. 5A. FIG. 6A is an enlarged view of neighborhood of theregion ABS of FIG. 5A. FIG. 6B is a cross section corresponding to theregion ABS of FIG. 6A. In the step, first, a nonmagnetic layer 12P isformed on the flattened top surfaces of the coil 9 and the insulatinglayers 10 and 11. The groove 120 will be formed later in the nonmagneticlayer 12P and the nonmagnetic layer 12P will be thereby formed into theencasing layer 12. Next, the polishing stopper layer 13 is formed bysputtering, for example, on the nonmagnetic layer 12P. Next, aphotoresist layer having a thickness of 1.0 μm, for example, is formedon the polishing stopper layer 13. The photoresist layer is thenpatterned to form a mask 31 for making the groove 120 of the encasinglayer 12. The mask 31 has an opening having a shape corresponding to thegroove 120.

Next, the polishing stopper layer 13 is selectively etched, using themask 31. The opening 13 a that penetrates is thereby formed in thepolishing stopper layer 13. The opening 13 a has a shape correspondingto the plane geometry of a magnetic layer 160 to be formed later. Aportion of the magnetic layer 160 will be formed into the pole layer 16.Furthermore, a portion of the nonmagnetic layer 12P exposed from theopening 13 a of the polishing stopper layer 13 is selectively etched soas to form the groove 120 in the nonmagnetic layer 12P. The mask 31 isthen removed. The nonmagnetic layer 12P is formed into the encasinglayer 12 by forming the groove 120 therein. The polishing stopper layer13 indicates the level at which polishing to be performed later isstopped. The edge of the opening 13 a of the polishing stopper layer 13is located directly above the edge of the groove 120 located in the topsurface of the encasing layer 12.

The etching of each of the polishing stopper layer 13 and thenonmagnetic layer 12P is performed by reactive ion etching or ion beametching, for example. The etching for forming the groove 120 in thenonmagnetic layer 12P is performed such that the walls of the groove 120corresponding to both sides of the track width defining portion 16A ofthe pole layer 16 each form an angle that falls within a range of 5 to12 degrees inclusive, for example, with respect to the directionorthogonal to the top surface of the substrate 1.

As shown in FIG. 5A and FIG. 6A, the groove 120 includes a portion 120 acorresponding to the pole layer, indicator portions 120 b and 120 c, anda coupling portion 120 d. The portion 120 a corresponding to the polelayer is a portion in which the pole layer 16 will be placed later. Theportion 120 a is shown as a portion of the groove 120 on the right handof the region ABS in FIG. 5A, and a portion of the groove 120 locatedhigher than the region ABS in FIG. 6A. The indicator portions 120 b and120 c correspond to the indicators of the invention, and each serve as areference for indicating the location of the ABS. The shape of each ofthe indicator portions 120 b and 120 c in the top surface of thenonmagnetic layer 12P is rectangular. The coupling portion 120 d is aportion of the groove 120 for coupling the portion 120 a to theindicator portions 120 b and 120 c. The portion 120 a corresponds to oneof the ‘grooves that accommodate the pole layers’ of the invention. Theindicator portions 120 b and 120 c correspond to the ‘other grooves thatform the indicators’.

Reference is now made to FIG. 1 to describe the indicator portions 120 band 120 c in detail. FIG. 1 shows the indicator portions 120 b and 120 cand a neighborhood thereof. In FIG. 5A to FIG. 16A and FIG. 5B to FIG.16B, the track width is shown greater, compared with FIG. 1, toillustrate details of the portion around the pole layer 16. As shown inFIG. 1, the indicator portion 120 b has two ends 120 b 1 and 120 b 2each of which is parallel to the region ABS. Similarly, the indicatorportion 120 c has two ends 120 c 1 and 120 c 2 each of which is parallelto the region ABS. The ends 120 b 1 and 120 c 1 are located closer tothe region ABS than the ends 120 b 2 and 120 c 2. The distance betweenthe region ABS and the end 120 b 1 is equal to the distance between theregion ABS and the end 120 c 1. Similarly, the distance between theregion ABS and the end 120 b 2 is equal to the distance between theregion ABS and the end 120 c 2. In the embodiment, the location of theends 120 b 1 and 120 c 1 serves as a reference for indicating thelocation of the region ABS. Therefore, the distance D1 between theregion ABS and the ends 120 b 1 and 120 c 1 is designed to be of aspecific value. Furthermore, the distance between the indicator portion120 b and the track width defining portion 16A taken in the direction ofwidth thereof is equal to the distance between the indicator portion 120c and the track width defining portion 16A. This distance is defined asD3.

Next, the opening 13 a of the polishing stopper layer 13 is observed,using an electron microscope. It is preferred to use a criticaldimension measurement scanning electron microscope as the electronmicroscope. Since the edge of the opening 13 a is located directly abovethe edge of the groove 120 located in the top surface of the encasinglayer 12, the shape of the opening 13 a coincides with the shape of thegroove 120 taken in the top surface of the encasing layer 12. Therefore,it is possible to obtain the shape of the groove 120 taken in the topsurface of the encasing layer 12 by observing the opening 13 a.

By observing the opening 13 a, the location of the region ABS isobtained in the following manner. As described above, the location ofthe ends 120 b 1 and 120 c 1 serves as the reference for indicating thelocation of the region ABS. Therefore, it is possible to obtain thelocation of the region ABS by observing the opening 13 a and measuringthe location of the ends 120 b 1 and 120 c 1. If the distance D1 betweenthe region ABS and the ends 120 b 1, 120 c 1 is other than zero, theregion ABS is placed in a location away from the ends 120 b 1 and 120 c1 by the distance D1. If the distance D1 between the region ABS and theends 120 b 1, 120 c 1 is zero, the location of the region ABS is thelocation of the ends 120 b 1 and 120 c 1.

As shown in FIG. 2, the track width is equal to the length of the secondside A2 of the end face of the track width defining portion 16A locatedin the medium facing surface 30. The track width is equal to the widthof the groove 120 taken in the top surface of the encasing layer 12 atthe location of the region ABS. Therefore, it is possible to obtain thetrack width by measuring the width of the groove 120 in the top surfaceof the encasing layer 12 at the location of the region ABS.

The indicator portions 120 b and 120 c are located at a height the sameas the portion 120 a corresponding to the pole layer in a neighborhoodof the region in which the track width defining portion 16A is located.Therefore, it is possible to determine the location of the region ABSand to obtain the track width through a single observation using anelectron microscope.

The indicator portions 120 b and 120 c are disposed on both sides of thetrack width defining portion 16A to be formed later, the sides beingopposed to each other in the direction of width of the defining portion16A. In addition, the distance between the region ABS and the end 120 b1 is equal to the distance between the region ABS and the end 120 c 1.Therefore, the region ABS is parallel to an imaginary straight line thatis in contact with the ends 120 b 1 and 120 c 1. Based on the foregoingfindings of the embodiment, it is possible to obtain the location of theregion ABS with higher accuracy, referring to the two indicator portions120 b and 120 c.

If the track width is as small as 0.08 to 0.12 μm, in particular, animage of high magnification is required to measure the track width byusing an electron microscope. It is preferred that the distance D1 is adistance that can be recognized in an image of high magnificationobtained by an electron microscope when the indicator portions 120 b and120 c and the neighborhood thereof are observed by the electronmicroscope. This indicates that the distance D1 preferably falls withina range of 0 to 3.0 μm inclusive, and more preferably a range of 0 to1.0 μm inclusive. Since it is possible to recognize the location of theregion ABS with higher accuracy as the distance D1 is reduced, thedistance D1 still more preferably falls within a range of 0 to 0.2 μminclusive.

When the location of the region ABS is obtained from the location of theindicator portions 120 b and 120 c based on the image of highmagnification obtained by the electron microscope as mentioned above,and the track width is measured based on the location of the region ABS,it is possible to recognize the location of the region ABS and the trackwidth with higher accuracy as the distance D3 is reduced. This indicatesthat the distance D3 preferably falls within a range of 0.1 to 5.0 μminclusive.

As shown in FIG. 44, when both sides of the track width defining portionare etched to reduce the track width, indicators near the track widthdefining portion disturb this etching. Therefore, in this case, it isdifficult to dispose the indicators near the track width definingportion. According to the embodiment, in contrast, the pole layer 16 isdisposed in the groove 120 of the encasing layer 12, and the track widthis determined by the width of the groove 120 taken in the top surface ofthe encasing layer 12 at the location of the region ABS. Therefore, theembodiment does not include any step of etching the sides of the trackwidth defining portion. It is therefore possible to dispose theindicator portions 120 b and 120 c near the track width defining portion16A.

A case is now assumed wherein the polishing stopper layer 13 is notdisposed on the top surface of the encasing layer 12 and the encasinglayer 12 is made of an insulating material such as alumina. In thiscase, if an attempt is made to observe the groove 120 in the top surfaceof the encasing layer 12 by an electron microscope, electric chargesaccumulate on the top surface of the encasing layer 12 and it isimpossible to obtain a correct image. According to the embodiment, incontrast, the polishing stopper layer 13 made of a conductive materialis disposed on the top surface of the encasing layer 12. In addition,the edge of the opening 13 a of the polishing stopper layer 13 islocated directly above the edge of the groove 120 located in the topsurface of the encasing layer 12. As a result, a correct image isobtained when the polishing stopper layer 13 is observed by an electronmicroscope, and it is thereby possible to measure the geometry of theopening 13 a of the polishing stopper layer 13 with accuracy. It isthereby possible to measure the geometry of the groove 120 in the topsurface of the encasing layer 12 with accuracy.

When the width of the groove 120 in the top surface of the encasinglayer 12 at the location of the region ABS is measured by an electronmicroscope as described above, the width of the bottom of the groove 120at the location of the region ABS may be measured at the same time. Itis possible to obtain the angle formed by the wall of the groove 120with respect to the direction orthogonal to the top surface of thesubstrate 1 by calculation if the depth of the groove 120 is obtained inaddition to the width of the groove 120 in the top surface of theencasing layer 12 and the width of the bottom of the groove 120. Here,it is possible to obtain the depth of the groove 120 by preparing asample for measuring the depth of the groove 120, cutting the sample sothat the cross section shown in FIG. 6B appears, and observing the crosssection by a scanning electron microscope, for example. If thenonmagnetic layer 12P is etched by reactive ion etching, the etchingrate of the nonmagnetic layer 12P is nearly constant. Consequently, aslong as the etching period is constant, the depth of the groove 120 isnearly uniform, too. Therefore, if the depth of the groove 120 ismeasured in advance by using the sample for measuring the depth, thedepth of the groove 120 is obtained without measuring in the course ofmanufacturing process of the magnetic head.

FIG. 7A, FIG. 7B, FIG. 8A and FIG. 8B illustrate the following step.FIG. 7A shows the top surface of the layered structure in the course ofmanufacturing process of the magnetic head. FIG. 7B shows a crosssection of the layered structure orthogonal to the medium facing surfaceand the substrate. FIG. 7B is a cross section taken along line B-B ofFIG. 7A. FIG. 8A is an enlarged view of neighborhood of the region ABSof FIG. 7A. FIG. 8B is a cross section corresponding to the region ABSof FIG. 8A. In the step, a magnetic layer 161P is formed in the groove120 of the encasing layer 12 and on the polishing stopper layer 13. Themagnetic layer 161P is formed by sputtering or ion beam deposition(hereinafter referred to as IBD), for example. If the magnetic layer161P is formed by sputtering, it is preferred to employ collimationsputtring or long throw sputtering.

FIG. 9A, FIG. 9B, FIG. 10A and FIG. 10B illustrate the following step.FIG. 9A shows the top surface of the layered structure in the course ofmanufacturing process of the magnetic head. FIG. 9B illustrates a crosssection of the layered structure orthogonal to the medium facing surfaceand the substrate. FIG. 9B is a cross section taken along line B-B ofFIG. 9A. FIG. 10A is an enlarged view of neighborhood of the region ABSof FIG. 9A. FIG. 10B is a cross section corresponding to the region ABSof FIG. 10A. In the step, first, a magnetic layer 162P is formed on themagnetic layer 161P. The magnetic layer 162P is formed by frame plating,for example. In this case, the magnetic layer 161P is used as anelectrode for plating. In FIG. 9A, FIG. 10A and FIG. 10B, numeral 163indicates an unwanted plating layer formed outside the frame. Next, thelayered structure made up of the magnetic layer 161P and the polishingstopper layer 13 except portions below the magnetic layer 162P and theplating layer 163 is removed by etching.

FIG. 11A, FIG. 11B, FIG. 12A and FIG. 12B illustrate the following step.FIG. 11A shows the top surface of the layered structure in the course ofmanufacturing process of the magnetic head. FIG. 11B illustrates a crosssection of the layered structure orthogonal to the medium facing surfaceand the substrate. FIG. 11B is a cross section taken along line B-B ofFIG. 11A. FIG. 12A is an enlarged view of neighborhood of the region ABSof FIG. 11A. FIG. 12B is a cross section corresponding to the region ABSof FIG. 12A. In the step, first, a coating layer 32 made of alumina, forexample, and having a thickness of 1.0 to 1.5 μm, for example, is formedon the entire top surface of the layered structure. Next, the coatinglayer 32, the magnetic layer 162P and the magnetic layer 161P arepolished by CMP, for example, until the polishing stopper layer 13 isexposed, and the top surfaces of the polishing stopper layer 13, themagnetic layer 161P and the magnetic layer 162P are thereby flattened.As a result, portions of the magnetic layers 161P and 162P disposed onthe top surface of the polishing stopper layer 13 are removed. Theremaining portions of the magnetic layers 161P and 162P are hereinaftercalled magnetic layers 161Q and 162Q, respectively. A combination of themagnetic layers 161Q and 162Q is called a magnetic layer 160.

If the coating layer 32, the magnetic layer 162P and the magnetic layer161P are polished by CMP, such a slurry is used that polishing isstopped when the polishing stopper layer 13 is exposed, such as analumina-base slurry. It is possible to control the thickness of themagnetic layer 160 that will be the pole layer 16 later with accuracy bystopping the polishing when the polishing stopper layer 13 is exposed asthus described.

As shown in FIG. 11A and FIG. 12A, the magnetic layer 160 incorporates aportion 160 a corresponding to the pole layer, indicator portions 160 band 160 c, and a coupling portion 160 d. The portion 160 a is a portionto be the pole layer 16 later, and this is a portion of the magneticlayer 160 shown on a right side of the region ABS in FIG. 11A and shownabove the region ABS in FIG. 12A. The indicator portions 160 b and 160 ccorrespond to the indicators of the invention, and each serve as areference for indicating the location of the region ABS. Each of theindicator portions 160 b and 160 c has a plane geometry that isrectangle-shaped. The coupling portion 160 d is a portion for couplingthe portion 160 a and the indicator portions 160 b, 160 c of themagnetic layer 160 to each other.

As shown in FIG. 1, the plane geometries of the portion 160 a, theindicator portions 160 b and 160 c, and the coupling portion 160 d arethe same as the geometries of the portion 120 a, the indicator portions120 b and 120 c, and the coupling portion 120 d, respectively, in thetop surface of the encasing layer 12. The portion 160 a includes thetrack width defining portion 16A and the wide portion 16B. The indicatorportion 160 b has two ends 160 b 1 and 160 b 2 each of which is parallelto the region ABS. Similarly, the indicator portion 160 c has two ends160 c 1 and 160 c 2 each of which is parallel to the region ABS. Theends 160 b 1 and 160 c 1 are located closer to the region ABS than theends 160 b 2 and 160 c 2. The distance between the region ABS and theend 160 b 1 is equal to the distance between the region ABS and the end160 c 1. Similarly, the distance between the region ABS and the end 160b 2 is equal to the distance between the region ABS and the end 160 c 2.In the embodiment, the location of the ends 160 b 1 and 160 c 1 servesas a reference for indicating the location of the region ABS, as thelocation of the ends 120 b 1 and 120 c 1. The distance between theregion ABS and the ends 160 b 1, 160 c 1 is equal to the distance D1between the region ABS and the ends 120 b 1, 120 c 1. The distance D1 isdesigned to be of a specific value. Furthermore, the distance betweeneach of the indicator portions 160 b, 160 c and the track width definingportion 16A taken in the direction of width thereof is defined as D3.The preferred ranges of the distances D1 and D3 are described above.

The method of obtaining the location of the region ABS and the trackwidth by observing the opening 13 a of the polishing stopper layer 13through the use of an electron microscope is described above. In asimilar manner, it is possible to obtain the location of the region ABSand the track width by observing the magnetic layer 160 through the useof an electron microscope. That is, as described above, the location ofthe ends 160 b 1 and 160 c 1 serves as the reference for indicating thelocation of the region ABS. Therefore, it is possible to obtain thelocation of the region ABS by observing the magnetic layer 160 andmeasuring the location of the ends 160 b 1 and 160 c 1. It is furtherpossible to obtain the track width by measuring the width of themagnetic layer 160 at the location of the region ABS. If the distance D1between the region ABS and the ends 160 b 1, 160 c 1 is other than zero,the region ABS is placed in a location away from the ends 160 b 1 and160 c 1 by the distance D1. If the distance D1 is zero, the location ofthe region ABS is the location of the ends 160 b 1 and 160 c 1. Themagnetic layer 160 is conductive. Therefore, it is possible to obtain acorrect image of the magnetic layer 160 by an electron microscope.

The indicator portions 160 b and 160 c are located at a height the sameas the portion 160 a corresponding to the pole layer in a neighborhoodof the region in which the track width defining portion 16A is located.Therefore, it is possible to determine the location of the region ABSand to obtain the track width through a single observation using anelectron microscope.

The indicator portions 160 b and 160 c are disposed on both sides of thetrack width defining portion 16A, the sides being opposed to each otherin the direction of width of the defining portion 16A. In addition, thedistance between the region ABS and the end 160 b 1 is equal to thedistance between the region ABS and the end 160 c 1. Therefore, theregion ABS is parallel to an imaginary straight line that is in contactwith the ends 160 b 1 and 160 c 1. Based on the foregoing findings ofthe embodiment, it is possible to obtain the location of the region ABSwith higher accuracy, referring to the two indicator portions 160 b and160 c.

According to the embodiment, each of the pole layer 16 and the indicatorportions 160 b and 160 c that are made up of portions of the magneticlayer 160 is conductive. In addition, the indicator portions 160 b and160 c are electrically connected to the pole layer 160. Therefore, whenthe indicator portions 160 b and 160 c are observed by an electronmicroscope, it is possible to prevent electric charges from accumulatingon the indicator portions 160 b and 160 c. In addition, the potential ofthe indicator portions 160 b and 160 c is the same as that of the polelayer 16, and it is thereby possible to obtain correct images of theindicator portions 160 b and 160 c together with the pole layer 16. Itis thereby possible to obtain the location of the region ABS with higheraccuracy.

FIG. 13A and FIG. 13B illustrate the following step. FIG. 13A shows across section of the layered structure in the course of manufacturingprocess of the magnetic head, the cross section being orthogonal to themedium facing surface and the substrate. FIG. 13B is an enlarged view ofcross section corresponding to the region ABS of FIG. 13A. In the step,a portion of the polishing stopper layer 13 located outside the coatinglayer 32 is removed by etching.

FIG. 14A and FIG. 14B illustrate the following step. FIG. 14A shows across section of the layered structure in the course of manufacturingprocess of the magnetic head, the cross section being orthogonal to themedium facing surface and the substrate. FIG. 14B is an enlarged view ofcross section corresponding to the region ABS of FIG. 14A. In the step,first, the gap layer 18 is formed on the entire top surface of thelayered structure. Next, a region of the gap layer 18 in which the yokelayer 20B is to be formed is selectively etched to form an opening inthe gap layer 18. Next, the first layer 20A is formed on the gap layer18, and the yoke layer 20B is formed on a portion of the magnetic layer160 where the opening of the gap layer 18 is formed. The first layer 20Aand the yoke layer 20B may be formed by frame plating or by making amagnetic layer through sputtering and then selectively etching themagnetic layer. A method of selectively etching the magnetic layer maybe, for example, forming an alumina layer on the magnetic layer, forminga mask on the alumina layer by frame plating, and etching the aluminalayer and the magnetic layer using the mask. Next, the nonmagnetic layer21 is formed on the entire top surface of the layered structure.

FIG. 15A and FIG. 15B illustrate the following step. FIG. 15A shows across section of the layered structure in the course of manufacturingprocess of the magnetic head, the cross section being orthogonal to themedium facing surface and the substrate. FIG. 15B is an enlarged view ofcross section corresponding to the region ABS of FIG. 15A. In the step,first, the nonmagnetic layer 21 is polished by CMP, for example, so thatthe first layer 20A and the yoke layer 20B are exposed, and the topsurfaces of the first layer 20A, the yoke layer 20B and the nonmagneticlayer 21 are flattened. Next, the insulating layer 22 having a thicknessthat falls within a range of 0.2 to 0.3 μm inclusive, for example, isformed by a method such as sputtering on the entire top surface of thelayered structure. Next, the insulating layer 22 except a portion onwhich the coil 23 and the insulating layer 24 will be disposed later isremoved by etching. Next, the coil 23 is formed by frame plating, forexample, on the insulating layer 22. Next, the second layer 20C and thecoupling layer 20D are formed by frame plating, for example.Alternatively, the coil 23 may be formed after the second layer 20C andthe coupling layer 20D are formed.

FIG. 16A and FIG. 16B illustrate the following step. FIG. 16A shows across section of the layered structure in the course of manufacturingprocess of the magnetic head, the cross section being orthogonal to themedium facing surface and the substrate. FIG. 16B is an enlarged view ofcross section corresponding to the region ABS of FIG. 16A. In the step,first, the insulating layer 24 made of photoresist, for example, isselectively formed in the space between adjacent ones of the turns ofthe coil 23 and around the coil 23. Next, an insulating layer not shownhaving a thickness of 4 to 4.5 μm, for example, is formed on the entiretop surface of the layered structure. Next, the insulating layer ispolished by CMP, for example, so that the second layer 20C, the couplinglayer 20D and the coil 23 are exposed, and the top surfaces of thesecond layer 20C, the coupling layer 20D, the coil 23 and the insulatinglayer 24 are thereby flattened. Next, the insulating layer 25 is formedon the coil 23 and the insulating layer 24. Next, the third layer 20E isformed by frame plating, for example, to complete the shield layer 20.

Next, although not shown, a protection layer is formed to cover theentire top surface of the layered structure. Wiring and terminals arethen formed on the protection layer. In such a manner, components of aplurality of magnetic heads including a plurality of sets of pole layer16 and coil 23 are formed in the single substrate 1. The magnetic headsubstructure is thus fabricated in which a plurality of rows of pre-headportions that will be magnetic heads later are aligned. The magnetichead substructure is cut in a neighborhood of the region ABS. A surfaceformed by cutting the magnetic head substructure is polished to form themedium facing surfaces 30. Furthermore, a plurality of pre-head portionsare separated from one another by cutting the substructure, and aplurality of magnetic heads are thereby formed. When the pre-headportions are separated, the magnetic layers 161Q and 162Q become thefirst layer 161 and the second layer 162, respectively.

Reference is now made to FIG. 17 to FIG. 19 to describe a specificexample of the step of fabricating a plurality of magnetic heads byseparating the magnetic head substructure. FIG. 17 is a top view of themagnetic head substructure. As shown in FIG. 17, the magnetic headsubstructure 210 includes a plurality of rows of pre-head portions 211.In the step of fabricating the magnetic heads, first, the substructure210 is cut in the positions indicated with dashed lines of FIG. 17 toform head aggregates 212 each of which includes a row of plurality ofpre-head portions 211. Next, a surface (the lower surface in FIG. 17)formed in each head aggregate 212 by cutting the substructure 210 ispolished (lapped) to form the medium facing surfaces 30 of the pre-headportions 211 that the head aggregate 212 includes.

Reference is now made to FIG. 18 and FIG. 19 to describe a method offorming the medium facing surfaces 30 by lapping the head aggregate 212.In this method, the head aggregate 212 is lapped so that the MR heightsand the throat heights of the pre-head portions 211 are made equal whilethe resistances of the MR elements 5 that the head aggregate 212includes are detected. The MR height is the length of each of the MRelements 5 taken in the direction orthogonal to the medium facingsurface 30.

FIG. 18 is a perspective view illustrating a schematic configuration ofa lapping apparatus for lapping the head aggregate 212. This lappingapparatus 251 comprises: a table 260; a rotating lapping table 261provided on the table 260; a strut 262 provided on the table 260 on aside of the rotating lapping table 261; and a supporter 270 attached tothe strut 262 through an arm 263. The rotating lapping table 261 has alapping plate (surface plate) 261 a to come to contact with the surfaceto be the medium facing surfaces 30 of the pre-head portions 211 thatthe head aggregate 212 includes.

The supporter 270 comprises a jig retainer 273 and three loadapplication rods 275A, 275B and 275C placed in front of the jig retainer273 at equal spacings. A jig 280 is to be fixed to the jig retainer 273.The jig 280 has three load application sections each of which is in theshape of a hole having an oblong cross section. Load application pinsare provided at the lower ends of the load application rods 275A, 275Band 275C, respectively. The load application pins have respective headsto be inserted to the load application sections (holes) of the jig 280,the heads each having an oblong cross section. Each of the loadapplication pins is driven by an actuator (not shown) in the vertical,horizontal (along the length of the jig 280) and rotational directions.

The jig 280 has a retainer for retaining the head aggregate 212. Withthis jig 280, the retainer and the head aggregate 212 are deformed byapplying loads in various directions to the three load applicationsections. It is thereby possible that the surface to be the mediumfacing surfaces 30 of the pre-head portions 211 that the head aggregate212 includes is lapped while the throat heights and MR heights of aplurality of pre-head portions 211 that the head aggregate 212 includesare controlled to be of target values.

FIG. 19 is a block diagram showing an example of circuit configurationof the lapping apparatus shown in FIG. 18. This lapping apparatuscomprises: nine actuators 291 to 299 for applying loads in the threedirections to the load application sections of the jig 280; a controller286 for controlling the actuators 291 to 299 through monitoring theresistance values of a plurality of MR elements 5 in the head aggregate212; and a multiplexer 287, connected to the MR elements 5 in the headaggregate 212 through a connector (not shown), for selectivelyconnecting one of the MR elements 5 to the controller 286.

In this lapping apparatus, the controller 286 monitors the resistancevalues of the MR elements 5 in the head aggregate 212 through themultiplexer 287, and controls the actuators 291 to 299 so that thethroat height and the MR height of each of the element sections 22 inthe head aggregate 212 fall within a tolerance.

Flying rails are formed by etching, for example, in the medium facingsurfaces 30 formed by lapping as described above. The head aggregate 212is then cut so that the pre-head portions 211 are separated from oneanother, and a plurality of magnetic heads are thereby formed.

The specific details of the step of fabricating the magnetic heads byseparating the magnetic head substructure are not limited to the exampledescribed with reference to FIG. 17 to FIG. 19. For example, themagnetic heads may be fabricated in the following manner. First, themagnetic head substructure 210 is cut to fabricate a first headaggregate that includes a plurality of rows of pre-head portions 211.Next, a surface of the first head aggregate is lapped to form the mediumfacing surfaces 30 of a single row of pre-head portions 211. Next, thefirst head aggregate is cut so that the single row of pre-head portions211 in which the medium facing surfaces 30 have been formed is separatedto be a second head aggregate. Next, the second head aggregate is cut sothat the pre-head portions 211 are separated from one another, and aplurality of magnetic heads are thereby fabricated.

According to the method of manufacturing the magnetic head and themagnetic head substructure of the embodiment, a plurality of indicators(120 b, 120 c, 160 b and 160 c) are formed in the substructure, whereineach of the indicators serves as a reference for indicating the locationof the region ABS in which the medium facing surfaces 30 of the magneticheads will be formed. As a result, it is possible in the course ofmanufacturing process of the magnetic heads to know the location of theregion ABS in which the medium facing surfaces will be formed. It isthereby possible to obtain the track width with accuracy. Furthermore,it is thereby possible to improve the efficiency in manufacturing themagnetic heads.

According to the embodiment, the indicator portions 120 b and 120 c asportions of the groove 120 of the encasing layer 12 and the indicatorportions 160 b and 160 c as portions of the magnetic layer 160 eachfunction as the indicators. To determine the location of the region ABSand the track width in the course of manufacturing process of themagnetic heads, at least one of the indicator portions 120 b, 120 c andthe indicator portions 160 b, 160 c may be observed.

In the example shown in FIG. 1, the indicator portions 120 b, 120 c, 160b and 160 c are located in a region that will not remain in eachmagnetic head, that is, in a region lower than the region ABS. However,at least part of the ends of the indicator portions 120 b, 120 c, 160 band 160 c may be located in a region that will remain in each magnetichead, that is, in a region higher than the region ABS of FIG. 1.

In the example shown in FIG. 1, the locations of the ends 120 b 1, 120 c1, 160 b 1 and 160 c 1 are used as the reference for indicating thelocation of the region ABS. However, the locations of the ends 120 b 2,120 c 2, 160 b 2 and 160 c 2 may be used as the reference for indicatingthe location of the region ABS.

According to the method of manufacturing the magnetic head and themagnetic head substructure of the embodiment, the polishing of themagnetic layers 161P and 162P is stopped when the polishing stopperlayer 13 is exposed. The edge of the opening 13 a of the polishingstopper layer 13 is located directly above the edge of the groove 120located in the top surface of the encasing layer 12. Therefore, adifference in level is hardly created between the top surface of thepolishing stopper layer 13 and the top surfaces of the magnetic layers161P and 162P when the polishing of the magnetic layers 161P and 162P isstopped. As a result, according to the embodiment, it is possible tocontrol the thickness of the pole layer 16 with accuracy. Furthermore,it is thereby possible to control the width of the top surface of thepole layer 16 with accuracy. As a result, it is possible to control thetrack width with accuracy. According to the embodiment, the sideportions of the pole layer 16 are not etched. As a result, it isimpossible that the neck height NH is made greater than a desired valueand/or the pole layer 16 goes out of a desired shape. It is thereforepossible to improve the overwrite property. Because of the foregoingfeatures of the embodiment, it is possible to form the pole layer 16with accuracy that has a small width and a shape capable of preventingthe problems resulting from the skew.

In the embodiment, after the coating layer 32 and the magnetic layers161P and 162P are polished until the polishing stopper layer 13 isexposed, the polishing stopper layer 13 may be selectively removed byreactive ion etching or ion beam etching, for example. Furthermore, themagnetic layers 161P and 162P may be slightly polished by CMP, forexample, to flatten the top surfaces of the encasing layer 12 and themagnetic layers 161P and 162P. Alternatively, after the coating layer 32and the magnetic layers 161P and 162P are polished until the polishingstopper layer 13 is exposed, ion beam etching may be performed to removethe polishing stopper layer 13 and to etch portions of the magneticlayers 161P and 162P, so that the top surfaces of the encasing layer 12and the magnetic layers 161P and 162P are flattened.

FIG. 20A and FIG. 20B illustrate a modification example of the method ofmanufacturing the magnetic head and the magnetic head substructure ofthe embodiment. FIG. 20A illustrates a cross section of the layeredstructure in the course of manufacturing process of the magnetic head,the cross section being orthogonal to the medium facing surface and thesubstrate. FIG. 20B is an enlarged view of a cross section correspondingto the region ABS of FIG. 20A. In FIG. 20A and FIG. 20B, the portioncloser to the substrate 1 than the encasing layer 12 is omitted.

The magnetic head of the modification example comprises an insulatinglayer 26 covering at least part of the coil 23 in place of theinsulating layers 24 and 25 of FIG. 3. The shield layer 20 of themodification example comprises a second layer 20F in place of the secondlayer 20C, the coupling layer 20D and the third layer 20E of FIG. 3. Thesecond layer 20F has an end located in the medium facing surface 30, andis disposed to couple the first layer 20A to the yoke layer 20B. Thesecond layer 20F includes a portion located on a side of the at leastpart of the coil 23 covered with the insulating layer 26, the side beingopposite to the pole layer 16. The second layer 20F includes a portionlocated between the medium facing surface 30 and the coil 23. In thisportion, the distance between the end located in the medium facingsurface 30 and the other end increases as the distance from the firstlayer 20A increases. The second layer 20F is made of CoNiFe or NiFe, forexample. The remainder of configuration of the magnetic head of themodification example is the same as that of the magnetic head shown inFIG. 2 and FIG. 3.

A method of manufacturing the magnetic head of the modification exampleincludes the steps up to the step of forming the coil 23 that are thesame as those of the method of manufacturing the magnetic head shown inFIG. 2 and FIG. 3. In the modification example, after the coil 23 isformed, the insulating layer 26 and the second layer 20F are formed oneby one. The following steps of the method of manufacturing the magnetichead of the modification example are the same as those of the method ofmanufacturing the magnetic head shown in FIG. 2 and FIG. 3.

Second Embodiment

A method of manufacturing a magnetic head and a magnetic headsubstructure of a second embodiment of the invention will now bedescribed. FIG. 21 illustrates indicator portions and a neighborhoodthereof of the embodiment. In the embodiment, the references forindicating the location of the region ABS are: the location of themiddle between ends 120 b 1 and 120 b 2; the location of the middlebetween ends 120 c 1 and 120 c 2; the location of the middle betweenends 160 b 1 and 160 b 2; and the location of the middle between ends160 c 1 and 160 c 2. Therefore, the distance D2 between the region ABSand each of the above-mentioned locations of the middles is designed tobe of a specific value. A preferred range of the distance D2 is the sameas that of the distance D1 of the first embodiment.

In FIG. 21, the indicator portions 120 b, 120 c, 160 b and 160 c arelocated in a region that will not remain in the magnetic head, that is,in a region lower than the region ABS. However, at least part of theends of the indicator portions 120 b, 120 c, 160 b and 160 c may belocated in a region that will remain in the magnetic head, that is, in aregion higher than the region ABS of FIG. 20A and FIG. 20B.

The shapes of the indicator portions 120 b, 120 c, 160 b and 160 c aredetermined by photolithography. As a result, there is a possibility thatthe sizes of the indicator portions 120 b, 120 c, 160 b and 160 c vary,depending on factors such as variations in amount of exposure ofphotolithography. However, even if the sizes of the indicator portions120 b, 120 c, 160 b and 160 c vary as such, there hardly occurvariations in the location of the middle between the ends 120 b 1 and120 b 2, the location of the middle between the ends 120 c 1 and 120 c2, the location of the middle between the ends 160 b 1 and 160 b 2, andthe location of the middle between the ends 160 c 1 and 160 c 2.Therefore, according to the embodiment, it is possible to suppressvariations in the locations as the references for indicating thelocation of the region ABS, and it is thereby possible to obtain thelocation of the region ABS with higher accuracy.

The remainder of configuration, operation and effects of the secondembodiment are similar to those of the first embodiment including themodification example.

Third Embodiment

Reference is now made to FIG. 22 and FIG. 23 to describe a method ofmanufacturing a magnetic head and a magnetic head substructure of athird embodiment of the invention. FIG. 22 and FIG. 23 each illustrateindicator portions and a neighborhood thereof of the third embodiment.In the embodiment, at least part of each of the indicators is located ina region that will remain in the magnetic head. FIG. 22 illustrates anexample in which part of each of the indicators is located in the regionthat will remain in the magnetic head. FIG. 23 illustrates an example inwhich the whole of each of the indicators is located in the region thatwill remain in the magnetic head.

In the example shown in FIG. 22, the middle between the ends 120 b 1 and120 b 2, the middle between the ends 120 c 1 and 120 c 2, the middlebetween the ends 160 b 1 and 160 b 2, and the middle between the ends160 c 1 and 160 c 2 are located in the region ABS. Therefore, thelocations of these middles are the references for indicating thelocation of the region ABS. In the example shown in FIG. 22, thedistance between the region ABS and each of the locations ofabove-mentioned middles is zero. However, this distance may be designedto be of a value other than zero. Alternatively, the locations of theends 120 b 1, 120 c 1, 160 b 1 and 160 c 1 or the locations of the ends120 b 2, 120 c 2, 160 b 2 and 160 c 2 may be used as the references forindicating the location of the region ABS.

In the example shown in FIG. 22, the indicator portions 120 b, 120 c,160 b and 160 c have portions that will remain in the magnetic head,that is, the portions located in a region higher than the region ABS ofFIG. 22. The length of these portions in the direction orthogonal to theregion ABS is equal to the neck height NH. Therefore, the portions ofthe indicator portions 120 b, 120 c, 160 b and 160 c that will remain inthe magnetic head indicate the neck height.

In the example shown in FIG. 23, the whole of each of the indicatorportions 120 b, 120 c, 160 b and 160 c is located in the region thatwill remain in the magnetic head, that is, in the region higher than theregion ABS of FIG. 23. In the example shown in FIG. 23, the ends 120 b2, 120 c 2, 160 b 2 and 160 c 2 are located in the region ABS.Therefore, the locations of the ends 120 b 2, 120 c 2, 160 b 2 and 160 c2 are the references for indicating the location of the region ABS. Inthe example shown in FIG. 23, the distance between the region ABS andeach of the ends 120 b 2, 120 c 2, 160 b 2 and 160 c 2 is zero.Alternatively, the locations of the ends 120 b 1, 120 c 1, 160 b 1 and160 c 1 may be used as the references for indicating the location of theregion ABS. Another alternative is that the location of the middlebetween the ends 120 b 1 and 120 b 2, the location of the middle betweenthe ends 120 c 1 and 120 c 2, the location of the middle between theends 160 b 1 and 160 b 2, and the location of the middle between theends 160 c 1 and 160 c 2 may be used as the references for indicatingthe location of the region ABS.

In the example shown in FIG. 23, the length of the indicator portions120 b, 120 c, 160 b and 160 c taken in the direction orthogonal to theregion ABS is equal to the neck height NH. Therefore, the indicatorportions 120 b, 120 c, 160 b and 160 c indicate the neck height NH.

According to the embodiment, the neck height NH may be obtained in thefollowing manner after the magnetic heads are completed. In this method,first, a specific number of magnetic heads are taken as samples fordetermining neck heights from a plurality of magnetic heads manufacturedout of a single substrate 1. Next, in the samples, etching is performedon portions around the portions of the indicator portions 120 b, 120 c,160 b and 160 c remaining in the magnetic heads. The length of each ofthese portions orthogonal to the medium facing surface 30 is thenmeasured. This length is equal to the neck height NH. Therefore, theneck height NH of each of the samples is obtained by measuring thislength. It is assumed that the neck heights NH of the magnetic headsthat are other than the samples but manufactured out of the samesubstrate 1 as the samples are nearly equal to the neck heights NH ofthe samples. According to the embodiment, the neck height NH is obtainedin such a manner after the magnetic heads are completed. It is therebypossible to confirm whether the neck height NH is of a desired valueafter the magnetic heads are completed.

The remainder of configuration, operation and effects of the thirdembodiment are similar to those of the first embodiment including themodification example.

Fourth Embodiment

Reference is now made to FIG. 24 to describe a method of manufacturing amagnetic head and a magnetic head substructure of a fourth embodiment ofthe invention. FIG. 24 illustrates indicators and a neighborhood thereofof the fourth embodiment. In the embodiment, grooves 120A, 120B and 120Cthat are separated from one another are formed in place of the groove120 of the first embodiment. A method of forming the grooves 120A, 120Band 120C is the same as that of the groove 120. The groove 120Aincorporates a portion 120Aa corresponding to the pole layer and anextended portion 120Ad. The portion 120Aa is a portion in which the polelayer 16 will be disposed later. The extended portion 120Ad is a portionconnected to the portion 120Aa and located in a region that will notremain in the magnetic head, that is, the region lower than the regionABS of FIG. 24. The grooves 120B and 120C correspond to the indicatorsof the invention and each serve as the reference for indicating thelocation of the region ABS. The shape of each of the grooves 120B and120C in the top surface of the nonmagnetic layer 12P is rectangular. Thegroove 120A corresponds to the ‘first groove’ of the invention. Theportion 120Aa corresponds to the ‘groove that accommodates the polelayer’ of the invention. The grooves 120B and 120C correspond to the‘second grooves’, and also correspond to the ‘other grooves that formthe indicators’ of the invention.

The grooves 120B and 120C have shapes the same as those of the indicatorportions 120 b and 120 c of the first embodiment, and are placed at thelocations the same as those of the indicator portions 120 b and 120 c.The groove 120B has two ends 120B1 and 120B2 each of which is parallelto the region ABS. Similarly, the groove 120C has two ends 120C1 and120C2 each of which is parallel to the region ABS. The ends 120B1 and120C1 are located closer to the region ABS than the ends 120B2 and120C2. The distance between the region ABS and the end 120B1 is equal tothe distance between the region ABS and the end 120C1. Similarly, thedistance between the region ABS and the end 120B2 is equal to thedistance between the region ABS and the end 120C2. In the embodiment,the location of the ends 120B1 and 120C1 serves as a reference forindicating the location of the region ABS. Therefore, the distance D1between the region ABS and the ends 120B1, 120C1 is designed to be of aspecific value. Furthermore, the distance between the grooves 120B, 120Cand the track width defining portion 16A taken in the direction of widththereof is defined as D3. The preferred ranges of the distances D1 andD3 are the same as those of the first embodiment.

In the embodiment, magnetic layers 160A, 160B and 160C that areseparated from one another are formed in place of the magnetic layer 160of the first embodiment. A method of forming the magnetic layers 160A,160B and 160C is the same as that of the magnetic layer 160. Themagnetic layer 160A incorporates a portion 160Aa corresponding to thepole layer and an extended portion 160Ad. The portion 160Aa is a portionthat will be the pole layer 16 later. The extended portion 160Ad is aportion connected to the portion 160Aa and located in a region that willnot remain in the magnetic head, that is, the region lower than theregion ABS of FIG. 24. The magnetic layers 160B and 160C correspond tothe indicators of the invention and each serve as the reference forindicating the location of the region ABS. Therefore, the indicators ofthe embodiment are made up of the magnetic layers 160B and 160C that arelocated at the height the same as the pole layer 16 (the magnetic layer160).

The magnetic layers 160A, 160B and 160C have plane geometries the sameas those of the grooves 120A, 120B and 120C in the top surface of theencasing layer 12. The magnetic layer 160B has two ends 160B1 and 160B2each of which is parallel to the region ABS. Similarly, the magneticlayer 160C has two ends 160C1 and 160C2 each of which is parallel to theregion ABS. The ends 160B1 and 160C1 are located closer to the regionABS than the ends 160B2 and 160C2. The distance between the region ABSand the end 160B1 is equal to the distance between the region ABS andthe end 160C1. Similarly, the distance between the region ABS and theend 160B2 is equal to the distance between the region ABS and the end160C2. In the embodiment, the location of the ends 160B1 and 160C1serves as a reference for indicating the location of the region ABS, asthe location of the ends 120B1 and 120C1. The distance between theregion ABS and the ends 160B1, 160C1 is equal to the distance D1 betweenthe region ABS and the ends 120B1, 120C1. The distance D1 is designed tobe of a specific value. Furthermore, the distance between the magneticlayers 160B, 160C and the track width defining portion 16A taken in thedirection of width thereof is defined as D3. The preferred ranges of thedistances D1 and D3 are described above.

In the fourth embodiment, as in the first embodiment, it is possible todetermine the location of the region ABS and the track width byobserving at least one of the grooves 120B, 120C and the magnetic layers160B, 160C by an electron microscope.

According to the embodiment, a connecting layer 170 made of a conductivematerial may be provided below the magnetic layers 160A, 160B and 160Cthat are conductive. The connecting layer 170 is in contact with thelower surfaces of the magnetic layers 160A, 160B and 160C, andelectrically connects the magnetic layers 160A, 160B and 160C to oneanother. As a result, when the magnetic layers 160A, 160B and 160C areobserved by an electron microscope, it is possible to prevent electriccharges from accumulating on the magnetic layers 160B and 160C. Inaddition, the potential of the magnetic layers 160B and 160C is the sameas that of the magnetic layer 160A, and it is thereby possible to obtaincorrect images of the magnetic layers 160B and 160C together with themagnetic layer 160A. It is thereby possible to obtain the location ofthe region ABS with higher accuracy.

The remainder of configuration, operation and effects of the fourthembodiment are similar to those of the first embodiment including themodification example.

In the fourth embodiment, as in the second embodiment, the location ofthe middle between the ends 120B1 and 120B2, the location of the middlebetween the ends 120C1 and 120C2, the location of the middle between theends 160B1 and 160B2, and the location of the middle between the ends160C1 and 160C2 may be used as the references for indicating thelocation of the region ABS. Alternatively, the locations of the ends120B2, 120C2, 160B2 and 160C2 may be used as the references forindicating the location of the region ABS. As in the third embodiment,at least part of each of the indicators (the grooves 120B and 120C andthe magnetic layers 160B and 160C) may be placed in a region that willremain in the magnetic head. Furthermore, the part of each of theindicators remaining in the magnetic head may indicate the neck heightNH.

Fifth Embodiment

Reference is now made to FIG. 25A to FIG. 33A and FIG. 25B to FIG. 33Bto describe a method of manufacturing a magnetic head and a magnetichead substructure of a fifth embodiment of the invention. The method ofmanufacturing the magnetic head of the fifth embodiment includes thesteps up to the step of forming the groove 120 in the nonmagnetic layer12P that are the same as those of the first embodiment. In the fifthembodiment, however, a lower polishing stopper layer 33 is formed on thenonmagnetic layer 12P in place of the polishing stopper layer 13 of thefirst embodiment. The material, thickness and forming method of thelower polishing stopper layer 33 are the same as those of the polishingstopper layer 13. The groove 120 is formed so that the nonmagnetic layer12P is formed into the encasing layer 12. Next, as in the firstembodiment, the location of the region ABS and the track width may beobtained by observing the opening of the lower polishing stopper layer33 through the use of an electron microscope after the mask 31 isremoved.

In the following step of the fifth embodiment, the pole layer 16 isformed in the groove 120 with a spacer layer 34 and an upper polishingstopper layer 35 disposed between the pole layer 16 and the groove 120.Therefore, the track width is of a value obtained by subtracting twicethe thickness of the spacer layer 34 and twice the thickness of theupper polishing stopper layer 35 from the width of the groove 120 takenin the top surface of the encasing layer 12 at the location of theregion ABS. It is possible to control the thicknesses of the spacerlayer 34 and the upper polishing stopper layer 35 with accuracy.Therefore, it is possible to obtain the track width by measuring theabove-mentioned width of the groove 120.

FIG. 25A, FIG. 25B, FIG. 26A and FIG. 26B illustrate the following step.FIG. 25A shows the top surface of the layered structure in the course ofmanufacturing process of the magnetic head. FIG. 25B illustrates a crosssection of the layered structure orthogonal to the medium facing surfaceand the substrate. FIG. 25B is a cross section taken along line B-B ofFIG. 25A. FIG. 26A is an enlarged view of neighborhood of the region ABSof FIG. 25A. FIG. 26B is a cross section corresponding to the region ABSof FIG. 26A. In the step, first, the spacer layer 34 made of anonmagnetic material is formed in the groove 120 of the encasing layer12 and on the lower polishing stopper layer 33. The thickness of thespacer layer 34 falls within a range of 20 to 50 nm inclusive, forexample.

The spacer layer 34 may be made of an insulating material or asemiconductor material, for example. The insulating material as thematerial of the spacer layer 34 may be any of alumina, silicon oxide(SiO_(x)), and silicon oxynitride (SiON). The semiconductor material asthe material of the spacer layer 34 may be polycrystalline silicon oramorphous silicon.

The spacer layer 34 may be formed by sputtering or CVD, for example. Itis possible to control the thickness of the spacer layer 34 withprecision. If the spacer layer 34 is formed by CVD, it is preferred toemploy a method called ‘atomic layer CVD’ (ALCVD) in which formation ofa single atomic layer is repeated. In this case, it is possible tocontrol the thickness of the spacer layer 34 with higher precision. Ifthe spacer layer 34 is formed using a semiconductor material, it ispreferred to form the spacer layer 34 by ALCVD at a low temperature(around 200° C.) or by low-pressure CVD at a low temperature. Thesemiconductor material as the material of the spacer layer 34 ispreferably undoped polycrystalline silicon or amorphous silicon.

Next, the upper polishing stopper layer 35 made of a nonmagneticmaterial is formed on the spacer layer 34. The upper polishing stopperlayer 35 is formed by sputtering or IBD, for example. If the upperpolishing stopper layer 35 is formed by sputtering, it is preferred toemploy collimation sputtering or long throw sputtering. The material ofthe upper polishing stopper layer 35 may be the same as that of thepolishing stopper layer 13 of the first embodiment. The thickness of theupper polishing stopper layer 35 falls within a range of 20 to 60 nm,for example.

Next, the magnetic layer 161P is formed on the upper polishing stopperlayer 35. The thickness of the magnetic layer 161P falls within a rangeof 40 to 60 nm, for example. The material and forming method of themagnetic layer 161P are the same as those of the first embodiment.

FIG. 27A, FIG. 27B, FIG. 28A and FIG. 28B illustrate the following step.FIG. 27A shows the top surface of the layered structure in the course ofmanufacturing process of the magnetic head. FIG. 27B illustrates a crosssection of the layered structure orthogonal to the medium facing surfaceand the substrate. FIG. 27B is a cross section taken along line B-B ofFIG. 27A. FIG. 28A is an enlarged view of neighborhood of the region ABSof FIG. 27A. FIG. 28B is a cross section corresponding to the region ABSof FIG. 28A. In the step, first, the magnetic layer 162P is formed onthe magnetic layer 161P. The magnetic layer 162P is formed by frameplating, for example. In this case, the magnetic layer 161P is used asan electrode for plating. If the upper polishing stopper layer 35 ismade of a conductive material, the upper polishing stopper layer 35 isused as an electrode for plating, too. In FIG. 27A, FIG. 28A and FIG.28B, numeral 163 indicates an unwanted plating layer formed outside theframe. Next, the layered structure made up of the magnetic layer 161P,the upper polishing stopper layer 35, the spacer layer 34 and the lowerpolishing stopper layer 33 except portions below the magnetic layer 162Pand the plating layer 163 are removed by etching.

FIG. 29A and FIG. 29B illustrate the following step. FIG. 29A shows across section of the layered structure in the course of manufacturingprocess of the magnetic head, the cross section being orthogonal to themedium facing surface and the substrate. FIG. 29B is an enlarged view ofcross section corresponding to the region ABS of FIG. 29A. In the step,first, the plating layer 163 is selectively removed. Next, the coatinglayer 32 made of alumina, for example, and having a thickness of 1.0 to1.5 μm, for example, is formed on the entire top surface of the layeredstructure.

FIG. 30A and FIG. 30B illustrate the following step. FIG. 30A shows across section of the layered structure in the course of manufacturingprocess of the magnetic head, the cross section being orthogonal to themedium facing surface and the substrate. FIG. 30B is an enlarged view ofcross section corresponding to the region ABS of FIG. 30A. In the step,the coating layer 32, the magnetic layer 162P and the magnetic layer161P are polished by CMP, for example, until the upper polishing stopperlayer 35 is exposed, and the top surfaces of the upper polishing stopperlayer 35, the magnetic layer 161P and the magnetic layer 162P arethereby flattened. If the coating layer 32, the magnetic layer 162P andthe magnetic layer 161P are polished by CMP, such a slurry is used thatpolishing is stopped when the upper polishing stopper layer 35 isexposed, such as an alumina-base slurry.

FIG. 31A and FIG. 31B illustrate the following step. FIG. 31A shows across section of the layered structure in the course of manufacturingprocess of the magnetic head, the cross section being orthogonal to themedium facing surface and the substrate. FIG. 31B is an enlarged view ofthe cross section corresponding to the region ABS of FIG. 31A. In thestep, first, reactive ion etching or ion beam etching is performed toselectively remove a portion of the upper polishing stopper layer 35exposed from the top surface of the layered structure. Next, the spacerlayer 34, the upper polishing stopper layer 35, the magnetic layer 161Pand the magnetic layer 162P are polished by CMP, for example, until thelower polishing stopper layer 33 is exposed, and the top surfaces of thelower polishing stopper layer 33, the spacer layer 34, the upperpolishing stopper layer 35, the magnetic layer 161P and the magneticlayer 162P are thereby flattened. As a result, portions of the magneticlayers 161P and 162P disposed on the top surface of the lower polishingstopper layer 33 are removed. The remaining portions of the magneticlayers 161P and 162P are hereinafter called magnetic layers 161Q and162Q, respectively. A combination of the magnetic layers 161Q and 162Qis called the magnetic layer 160.

If the spacer layer 34, the upper polishing stopper layer 35, themagnetic layer 161P and the magnetic layer 162P are polished by CMP,such a slurry is used that polishing is stopped when the lower polishingstopper layer 33 is exposed, such as an alumina-base slurry. It ispossible to control the thickness of the magnetic layer 160 that will bethe pole layer 16 later with accuracy by stopping the polishing when thelower polishing stopper layer 33 is exposed as thus described.

Next, as in the first embodiment, the location of the region ABS and thetrack width may be obtained by observing the magnetic layer 160 throughthe use of an electron microscope.

Next, the gap layer 18 is formed on the entire top surface of thelayered structure. A portion of the gap layer 18 in which the yoke layer20B is to be formed is selectively etched to form an opening in the gaplayer 18.

FIG. 32A and FIG. 32B illustrate the following step. FIG. 32A shows across section of the layered structure in the course of manufacturingprocess of the magnetic head, the cross section being orthogonal to themedium facing surface and the substrate. FIG. 32B is an enlarged view ofthe cross section corresponding to the region ABS of FIG. 32A. In thestep, first, the first layer 20A is formed on the gap layer 18, and theyoke layer 20B is formed on a portion of the magnetic layer 160 wherethe opening of the gap layer 18 is formed. Next, the nonmagnetic layer21 is formed on the entire top surface of the layered structure.

FIG. 33A and FIG. 33B illustrate the following step. FIG. 33A shows across section of the layered structure in the course of manufacturingprocess of the magnetic head, the cross section being orthogonal to themedium facing surface and the substrate. FIG. 33B is an enlarged view ofthe cross section corresponding to the region ABS of FIG. 33A. Thefollowing steps are the same as those of the first embodiment. That is,in the step, first, the nonmagnetic layer 21 is polished by CMP, forexample, so that the first layer 20A and the yoke layer 20B are exposed,and the top surfaces of the first layer 20A, the yoke layer 20B and thenonmagnetic layer 21 are thereby flattened. Next, the insulating layer22 is formed by a method such as sputtering on the entire top surface ofthe layered structure. Next, the insulating layer 22 except a portion onwhich the coil 23 and the insulating layer 24 will be disposed later isremoved by etching. Next, the coil 23 is formed on the insulating layer22 by frame plating, for example. Next, the second layer 20C and thecoupling layer 20D are formed by frame plating, for example.Alternatively, the coil 23 may be formed after the second layer 20C andthe coupling layer 20D are formed. Next, the insulating layer 24 isselectively formed in the space between adjacent turns of the coil 23and around the coil 23. Next, an insulating layer not shown is formed onthe entire top surface of the layered structure. Next, the insulatinglayer not shown is polished by CMP, for example, so that the secondlayer 20C, the coupling layer 20D and the coil 23 are exposed, and thetop surfaces of the second layer 20C, the coupling layer 20D, the coil23 and the insulating layer 24 are thereby flattened. Next, theinsulating layer 25 is formed on the coil 23 and the insulating layer24. Next, the third layer 20E is formed by frame plating, for example,to complete the shield layer 20.

Next, although not shown, a protection layer is formed to cover theentire top surface of the layered structure. Wiring and terminals arethen formed on the protection layer. In such a manner, components of aplurality of magnetic heads are formed in the single substrate 1. Themagnetic head substructure is thus formed in which a plurality of rowsof pre-head portions that will be the magnetic heads later are aligned.The magnetic head substructure is cut in a neighborhood of the regionABS. A surface formed by cutting the magnetic head substructure ispolished to form the medium facing surfaces 30. Furthermore, a pluralityof pre-head portions are separated from one another by cutting thesubstructure, and a plurality of magnetic heads are thereby formed. Whenthe pre-head portions are separated, the magnetic layers 161Q and 162Qbecome the first layer 161 and the second layer 162, respectively.

In the magnetic head of the embodiment, the pole layer 16 is disposed inthe groove 120 of the encasing layer 12 with the spacer layer 34 and theupper polishing stopper layer 35 disposed between the pole layer 16 andthe groove 120. It is thereby possible to further reduce the width ofthe top surface of the track width defining portion 16A for defining thetrack width.

As shown in FIG. 30A, FIG. 30B, FIG. 31A and FIG. 31B, the method ofmanufacturing the magnetic head of the embodiment includes: the firstpolishing step of polishing the coating layer 32 and the magnetic layers161P and 162P until the upper polishing stopper layer 35 is exposed; thestep of removing the upper polishing stopper layer 35 after the firstpolishing step; and the second polishing step of polishing the spacerlayer 34 and the magnetic layers 161P and 162P until the lower polishingstopper layer 33 is exposed after the upper polishing stopper layer 35is removed.

According to the embodiment, even if there is a great variation in thethickness of the magnetic layer 162P, it is possible through the firstpolishing step that the top surfaces of the magnetic layers 161P and162P are located at a level almost the same as the level at which thetop surface of the upper polishing stopper layer 35 is located. However,since the amount of polishing of the first polishing step is great, asmall difference in level may be created between the top surface of thestopper layer 35 and the top surfaces of the magnetic layers 161P and162P when the first polishing step is completed. However, according tothe fifth embodiment, the second polishing step with a small amount ofpolishing is performed after the stopper layer 35 is removed, and it isthereby possible to flatten the top surfaces of the lower polishingstopper layer 33, the magnetic layer 161P and the magnetic layer 162P,such that a difference in level is hardly created between the topsurface of the stopper layer 33 and the top surfaces of the magneticlayers 161P and 162P. As a result, according to the embodiment, it ispossible to control the thickness of the pole layer 16 made up of thefirst layer 161 and the second layer 162 with high accuracy. It istherefore possible to control the track width with high accuracy.

According to the fifth embodiment, if the upper polishing stopper layer35 is made of a conductive material, the stopper layer 35 and themagnetic layer 161P function as electrodes for plating when the magneticlayer 162P is formed by plating. Therefore, even if the magnetic layer161P is thin, it is possible to feed a sufficient current to the stopperlayer 35 and the magnetic layer 161P as the electrodes. It is therebypossible to form the magnetic layer 162P that is uniform in the groove120. As a result, according to the embodiment, it is possible to formthe pole layer 16 that is uniform with accuracy even if the groove 120has a small width.

In the fifth embodiment, the first layer 161 of the pole layer 16 may beomitted if the upper polishing stopper layer 35 is made of a conductivematerial. If the first layer 161 is omitted, a magnetic layer to be thepole layer 16 is formed by plating, for example, on the stopper layer35.

The remainder of configuration, operation and effects of the fifthembodiment are similar to those of the first embodiment including themodification example.

In the embodiment, after the spacer layer 34 and the magnetic layers161P and 162P are polished until the lower polishing stopper layer 33 isexposed, the polishing stopper layer 33 may be selectively removed byreactive ion etching or ion beam etching, for example. Furthermore, thespacer layer 34 and the magnetic layers 161P and 162P may be slightlypolished by CMP, for example, to flatten the top surfaces of theencasing layer 12, the spacer layer 34 and the magnetic layers 161P and162P. Alternatively, after the spacer layer 34 and the magnetic layers161P and 162P are polished until the polishing stopper layer 33 isexposed, ion beam etching may be performed to remove the polishingstopper layer 33 and to etch portions of the spacer layer 34 and themagnetic layers 161P and 162P, so that the top surfaces of the encasinglayer 12, the spacer layer 34 and the magnetic layers 161P and 162P areflattened.

Sixth Embodiment

A method of manufacturing a magnetic head and a magnetic headsubstructure of a sixth embodiment of the invention will now bedescribed. Reference is now made to FIG. 35A to FIG. 43A and FIG. 35B toFIG. 43B to describe the method of manufacturing the magnetic head ofthe embodiment. FIG. 35A to FIG. 43A illustrate a cross section of thelayered structure in the course of manufacturing process of the magnetichead, the cross section being orthogonal to the medium facing surfaceand the substrate. FIG. 35B to FIG. 43B illustrate a cross sectioncorresponding to the region ABS of FIG. 35A to FIG. 43A. In FIG. 35A toFIG. 43A and FIG. 35B to FIG. 43B, the coil 9, the insulating layers 10and 11, and the portion closer to the substrate 1 than the coil 9 andthe insulating layers 10 and 11 are omitted.

The method of manufacturing the magnetic head of the sixth embodimentincludes the steps up to the step of forming the coil 9 and theinsulating layers 10 and 11 on the insulating layer 8 and flattening thetop surfaces of the coil 9 and the insulating layers 10 and 11 that arethe same as those of the first embodiment.

FIG. 35A and FIG. 35B illustrate the following step. In the step, first,an insulating layer 41 made of an insulating material such as alumina isformed on the flattened top surfaces of the coil 9 and the insulatinglayers 10 and 11. Next, a yoke layer 42 made of a magnetic material anda conductive layer 43 made of a conductive material each of which has athickness of 1 μm, for example, are formed on the insulating layer 41 bya method such as frame plating. The yoke layer 42 may be made of CoNiFe,for example. The conductive layer 43 may be made of a material the sameas that of the yoke layer 42 and formed at the same time as the yokelayer 42. The shapes and arrangement of the yoke layer 42 and theconductive layer 43 will be described in detail later. Next, aninsulating layer 44 made of alumina, for example, and having a thicknessof 2 μm, for example, is formed on the entire top surface of the layeredstructure by a method such as sputtering.

Next, as shown in FIG. 36A and FIG. 36B, the insulating layer 44 ispolished by CMP, for example, so that the yoke layer 42 and theconductive layer 43 are exposed, and the top surfaces of the yoke layer42, the conductive layer 43 and the insulating layer 44 are therebyflattened.

FIG. 37A and FIG. 37B illustrate the following step. In the step, first,a layer 46P to be patterned that is made of a magnetic material isformed by sputtering, for example, on the flattened top surfaces of theyoke layer 42, the conductive layer 43 and the insulating layer 44. Thelayer 46P is made of CoFeN, for example. The layer 46P has a thicknessthat falls within a range of 0.2 to 0.4 μm inclusive, for example.

Next, an alumina layer 47 having a thickness of 1.2 μm, for example, isformed by sputtering, for example, on the layer 46P. Next, an etchingmask 48 made of CoFe or CoNiFe, for example, and having a thickness of0.3 to 0.6 μm, for example, is formed by frame plating on the aluminalayer 47. The mask 48 has a plane geometry corresponding to that of thepole layer to be formed.

FIG. 38A and FIG. 38B illustrate the following step. In the step, first,the alumina layer 47 is selectively etched, using the mask 48. Etchingof the alumina layer 47 is performed by reactive ion etching, forexample. Next, the layer 46P is selectively etched, using the portion ofthe alumina layer 47 remaining after the etching as a mask. Through thisetching, the layer 46P is patterned to be a magnetic layer 46Q that willbe the pole layer later. The magnetic layer 46Q includes a portion 46AQto be etched that will be formed into the track width defining portionby etching both side surfaces of the portion 46AQ to form slopedsurfaces. The etching of the layer 46P is performed by reactive ionetching or ion beam etching, for example.

FIG. 39A and FIG. 39B illustrate the following step. In the step, bothside surfaces of the portion 46AQ are etched by ion beam etching to makethe side surfaces of the portion 46AQ sloped, so that the width of thebottom surface of the portion 46AQ is smaller than the width of the topsurface of the portion 46AQ. To be specific, each of the side surfacesof the portion 46AQ is made to form an angle that falls within a rangeof 5 to 12 degrees inclusive, for example, with respect to the directionorthogonal to the top surface of the substrate 1. This etching isperformed such that the direction in which ion beams move forms an angleof 40 to 50 degrees, for example, with respect to the directionorthogonal to the top surface of the substrate 1. The magnetic layer 46Qin which the side surfaces of the portion 46AQ have been etched isdefined as a magnetic layer 46.

Reference is now made to FIG. 34 to describe the shapes and arrangementof the yoke layer 42, the conductive layer 43 and the magnetic layer 46.FIG. 34 is a top view of the yoke layer 42, the conductive layer 43 andthe magnetic layer 46 in the neighborhood of the region ABS. Themagnetic layer 46 incorporates a portion 46 a corresponding to the polelayer and an extended portion 46 b. The portion 46 a is a portion thatwill be the pole layer of the magnetic head later and that is located ina region higher than the region ABS of FIG. 34. The extended portion 46b is a portion connected to the portion 46 a and located in a regionthat will not remain in the magnetic head, that is, the region lowerthan the region ABS of FIG. 34. The portion 46 a incorporates a trackwidth defining portion 46A and a wide portion 46B.

The yoke layer 42 is disposed below the portion 46 a of the magneticlayer 46, and touches the portion 46 a. An end of the yoke layer 42closer to the region ABS is located at a distance from the region ABS.

The conductive layer 43 incorporates a connecting portion 43 a andindicator portions 43 b and 43 c. The indicator portions 43 b and 43 ccorrespond to the indicators of the invention and each serve as thereference for indicating the location of the region ABS. Each of theindicator portions 43 b and 43 c is rectangle-shaped. The connectingportion 43 a connects the indicator portions 43 b and 43 c to eachother. Part of the connecting portion 43 a is disposed below theextended portion 46 b of the magnetic layer 46, and touches the extendedportion 46 b.

The indicator portion 43 b has two ends 43 b 1 and 43 b 2 each of whichis parallel to the region ABS. Similarly, the indicator portion 43 c hastwo ends 43 c 1 and 43 c 2 each of which is parallel to the region ABS.The ends 43 b 1 and 43 c 1 are located closer to the region ABS than theends 43 b 2 and 43 c 2. The distance between the region ABS and the end43 b 1 is equal to the distance between the region ABS and the end 43 c1. Similarly, the distance between the region ABS and the end 43 b 2 isequal to the distance between the region ABS and the end 43 c 2. In theembodiment, the location of the ends 43 b 1 and 43 c 1 serves as areference for indicating the location of the region ABS. Therefore, thedistance D1 between the region ABS and the ends 43 b 1, 43 c 1 isdesigned to be of a specific value. Furthermore, the distance betweenthe indicator portions 43 b, 43 c and the track width defining portion46A taken in the direction of width thereof is defined as D3. Thepreferred ranges of the distances D1 and D3 are the same as those of thefirst embodiment.

According to the embodiment, the top surfaces of the indicator portions43 b, 43 c are exposed when both side surfaces of the portion 46AQ ofthe magnetic layer 46Q are etched and the magnetic layer 46Q is therebyformed into the magnetic layer 46. Therefore, it is possible to obtainthe location of the region ABS by observing the top surfaces of theindicator portions 43 b, 43 c through the use of an electron microscope.Furthermore, it is possible to obtain the track width by measuring thewidth of the top surface of the magnetic layer 46 at the location of theregion ABS.

According to the embodiment, the magnetic layer 46 and the indicatorportions 43 b and 43 c are conductive. In addition, the indicatorportions 43 b and 43 c are electrically connected to the magnetic layer46. Therefore, when the indicator portions 43 b and 43 c are observed byan electron microscope, it is possible to prevent electric charges fromaccumulating on the indicator portions 43 b and 43 c. In addition, thepotential of the indicator portions 43 b and 43 c is the same as that ofthe magnetic layer 46, and it is thereby possible to obtain correctimages of the indicator portions 43 b and 43 c together with themagnetic layer 46. It is thereby possible to obtain the location of theregion ABS with higher accuracy.

FIG. 40A and FIG. 40B illustrate the following step. In the step, first,a nonmagnetic layer 50 having a thickness equal to the thickness of themagnetic layer 46 is formed on the entire top surface of the layeredstructure. Next, a polishing stopper layer 51 having a thickness of 10to 20 nm, for example, is formed on the nonmagnetic layer 50 except aregion near the magnetic layer 46. The polishing stopper layer 51 ismade of a material the same as the material of the polishing stopperlayer 13 of the first embodiment. Next, an insulating film 52 made ofalumina, for example, and having a thickness of 0.3 to 0.8 μm, forexample, is formed on the entire top surface of the layered structure.

FIG. 41A and FIG. 41B illustrate the following step. In the step, first,the insulating film 52 and the nonmagnetic layer 50 are polished by CMP,for example. This polishing is stopped when the stopper layer 51 isexposed. Next, the stopper layer 51 is removed by reactive ion etchingor wet etching, for example. The top surface of the nonmagnetic layer 50is thereby exposed. Next, the top surfaces of the nonmagnetic layer 50and the insulating film 52 are slightly polished by CMP, for example, toexpose the top surface of the magnetic layer 46 and to flatten the topsurfaces of the magnetic layer 46 and the nonmagnetic layer 50. Thethickness of the pole layer that will be made up of the portion 46 a ofthe magnetic layer 46 later is thereby controlled to be of a desiredvalue.

FIG. 42A and FIG. 42B illustrate the following step. In the step, first,the gap layer 18 is formed on the entire top surface of the layeredstructure. Next, a portion of the gap layer 18 away from the region ABSis selectively etched to form an opening in the gap layer 18. Next, thefirst layer 20A is formed on the gap layer 18, and a coupling layer 20Gis formed on a portion of the magnetic layer 46 where the opening of thegap layer 18 is formed. The first layer 20A and the coupling layer 20Gmay be formed by frame plating or by making a magnetic layer throughsputtering and selectively etching the magnetic layer. Next, thenonmagnetic layer 53 is formed on the entire top surface of the layeredstructure. Next, the nonmagnetic layer 53 is polished by CMP, forexample, so that the first layer 20A and the coupling layer 20G areexposed, and the top surfaces of the first layer 20A, the coupling layer20G and the nonmagnetic layer 53 are flattened.

FIG. 43A and FIG. 43B illustrate the following step. In the step, first,the coil 23 is formed by frame plating, for example, on the nonmagneticlayer 53. Next, the second layer 20C is formed on the first layer 20Aand the coupling layer 20D is formed on the coupling layer 20G by frameplating, for example. Alternatively, the coil 23 may be formed after thesecond layer 20C and the coupling layer 20D are formed. Next, theinsulating layer 24 made of photoresist, for example, is selectivelyformed to cover the coil 23. Next, an insulating film not shown made ofalumina, for example, and having a thickness of 2.5 μm, for example, isformed on the entire top surface of the layered structure. Next, theinsulating film not shown and the insulating layer 24 are polished byCMP, for example, so that the second layer 20C, the coupling layer 20Dand the coil 23 are exposed, and the top surfaces of the second layer20C, the coupling layer 20D, the coil 23 and the insulating layer 24 arethereby flattened. Next, the insulating layer 25 made of alumina, forexample, and having a thickness of 0.2 μm, for example, is formed on thecoil 23 and the insulating layer 24.

Next, the third layer 20E is formed by frame plating, for example, tocomplete the shield layer 20 made up of the first layer 20A, the secondlayer 20C, the coupling layers 20G, 20D, and the third layer 20E.

Next, although not shown, a protection layer is formed to cover theentire top surface of the layered structure. Wiring and terminals arethen formed on the protection layer. In such a manner, components of aplurality of magnetic heads are formed in the single substrate 1. Themagnetic head substructure is thus formed in which a plurality of rowsof pre-head portions that will be the magnetic heads later are aligned.The magnetic head substructure is cut in a neighborhood of the regionABS. A surface formed by cutting the magnetic head substructure ispolished to form the medium facing surfaces 30. Furthermore, a pluralityof pre-head portions are separated from one another by cutting thesubstructure, and a plurality of magnetic heads are thereby formed. Whenthe pre-head portions are separated, the portion 46 a of the magneticlayer 46 becomes the pole layer. In the sixth embodiment, the shape ofthe end face of the track width defining portion located in the mediumfacing surface 30 is the same as that of the first embodiment.

In the sixth embodiment, the layer 46P is patterned by etching andthereby formed into the magnetic layer 46Q. Furthermore, the magneticlayer 46Q is etched and thereby formed into the magnetic layer 46. Thepole layer is made up of the magnetic layer 46. According to theembodiment, the conductive layer 43 including the indicator portions 43b and 43 c is located closer to the substrate 1 than the magnetic layer46. In other words, the indicators are made up of the conductive layer43 located closer to the substrate 1 than the pole layer. Therefore, theconductive layer 43 for making the indicators will not disturb etchingof the layer 46P and the magnetic layer 46Q.

The remainder of configuration, operation and effects of the sixthembodiment, except those resulting from differences in structure andforming method of the pole layer, are similar to those of the firstembodiment including the modification example.

In the sixth embodiment, as in the second embodiment, the location ofthe middle between the ends 43 b 1 and 43 b 2, and the location of themiddle between the ends 43 c 1 and 43 c 2 may be used as the referencesfor indicating the location of the region ABS. Alternatively, thelocations of the ends 43 b 2 and 43 c 2 may be used as the referencesfor indicating the location of the region ABS. As in the thirdembodiment, at least part of the indicator portions 43 b and 43 c may beplaced in a region that will remain in the magnetic head. Furthermore,the part of the indicator portions 43 b and 43 c remaining in themagnetic head may be designed to indicate the neck height NH.

The present invention is not limited to the foregoing embodiments butmay be practiced in still other ways. For example, a coil wound aroundthe pole layer in a helical manner may be provided in any of theembodiments in place of the flat-whorl-shaped coils 9 and 23.

In the foregoing embodiments, the magnetic head is disclosed, havingsuch a configuration that the read head is formed on the base body andthe write head is stacked on the read head. Alternatively, the read headmay be stacked on the write head.

The invention is applicable not only to magnetic heads for theperpendicular magnetic recording system but also to magnetic heads forthe longitudinal magnetic recording system.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

1. A method of manufacturing magnetic heads, each of the magnetic headscomprising: a medium facing surface that faces toward a recordingmedium; a coil that generates a magnetic field corresponding to data tobe written on the recording medium; and a pole layer that incorporates atrack width defining portion having an end face located in the mediumfacing surface, the pole layer allowing a magnetic flux corresponding tothe field generated by the coil to pass therethrough and generating awrite magnetic field for writing the data on the recording medium, themethod comprising the steps of: fabricating a magnetic head substructureby forming a plurality of sets of the pole layer and the coil in asubstrate, wherein a plurality of rows of pre-head portions that will bethe respective magnetic heads later are aligned in the substructure; andfabricating the magnetic heads by separating the pre-head portions fromone another through cutting the substructure, wherein the step offabricating the substructure includes the step of forming a plurality ofindicators each of which serves as a reference for indicating a locationof a region in which the medium facing surfaces of the magnetic headsare to be formed.
 2. The method according to claim 1, wherein: the endface of the track width defining portion located in the medium facingsurface has: a first side close to the substrate; a second side locatedopposite to the first side; a third side connecting an end of the firstside to an end of the second side; and a fourth side connecting theother end of the first side to the other end of the second side; thesecond side defines a track width; and the end face of the track widthdefining portion has a width that decreases as a distance from the firstside decreases.
 3. The method according to claim 1, wherein theindicators are formed on both sides of the track width defining portion,the sides being opposed to each other in a direction of width of thedefining portion, in the step of forming the indicators.
 4. The methodaccording to claim 3, wherein, in the substructure, each of the polelayers and the indicators is conductive, and the indicators areelectrically connected to the respective pole layers.
 5. The methodaccording to claim 1, wherein: the step of fabricating the substructurefurther includes the step of forming an encasing layer having groovesthat accommodate the pole layers; and the pole layers are disposed inthe grooves of the encasing layer.
 6. The method according to claim 5,wherein, in the step of forming the indicators, the indicators areformed of a layer located at a height the same as a height at which thepole layers are located.
 7. The method according to claim 1, wherein:the step of fabricating the substructure further includes the step offorming a magnetic layer having portions that will be the pole layers;and the indicators are made up of other portions of the magnetic layer.8. The method according to claim 7, wherein: the step of fabricating thesubstructure further includes the step of forming an encasing layerhaving a groove that accommodates the magnetic layer; and the magneticlayer is disposed in the groove of the encasing layer.
 9. The methodaccording to claim 1, wherein: the step of fabricating the substructurefurther includes the step of forming a magnetic layer having portionsthat will be the pole layers; and the indicators are made up of a layerother than the magnetic layer.
 10. The method according to claim 9,wherein: the step of fabricating the substructure further includes thestep of forming an encasing layer having a first groove thataccommodates the magnetic layer and second grooves that accommodate theindicators; the magnetic layer is formed in the first groove of theencasing layer; and the indicators are formed in the second grooves. 11.The method according to claim 1, wherein the indicators are formed of alayer located closer to the substrate than the pole layers in the stepof forming the indicators.
 12. The method according to claim 1, whereinthe indicators are formed of a layer having conductivity.
 13. The methodaccording to claim 1, wherein: the step of fabricating the substructurefurther includes the step of forming an encasing layer having groovesthat accommodate the pole layers and other grooves that form theindicators.
 14. The method according to claim 1, wherein each of theindicators have an end that is parallel to the region in which themedium facing surfaces are to be formed, and a location of the endserves as a reference for indicating a location of the region.
 15. Themethod according to claim 14, wherein a distance between a location ofthe reference and the region falls within a range of 0 to 1.0 μminclusive.
 16. The method according to claim 1, wherein each of theindicators have two ends that are parallel to the region in which themedium facing surfaces are to be formed, and a location of a middlebetween the two ends serves as a reference for indicating a location ofthe region.
 17. The method according to claim 16, wherein a distancebetween a location of the reference and the region falls within a rangeof 0 to 1.0 μm inclusive.
 18. The method according to claim 1, wherein,in the substructure, a distance between the track width defining portionand the indicators taken in a direction of width of the defining portionfalls within a range of 0.1 to 5.0 μm inclusive.
 19. The methodaccording to claim 1, wherein the indicators are located in a regionthat will not remain in the magnetic heads.
 20. The method according toclaim 1, wherein at least part of each of the indicators is located in aregion that will remain in the magnetic heads.
 21. The method accordingto claim 20, wherein the part of each of the indicators that remains inthe magnetic heads indicates a length of the track width definingportion taken in a direction orthogonal to the medium facing surface.22. The method according to claim 21, further comprising the step ofmeasuring the length of the track width defining portion taken in thedirection orthogonal to the medium facing surface by measuring a lengthof the part of each of the indicators that remains in the magnetic headstaken in the direction orthogonal to the medium facing surface, the stepbeing performed after the step of fabricating the magnetic heads. 23.The method according to claim 1, wherein the step of fabricating themagnetic heads includes the step of forming the medium facing surfacesby polishing a surface formed by cutting the substructure.
 24. Themethod according to claim 1, wherein the magnetic heads are those usedfor a perpendicular magnetic recording system.
 25. A magnetic headsubstructure used for manufacturing magnetic heads, each of the magneticheads comprising: a medium facing surface that faces toward a recordingmedium; a coil that generates a magnetic field corresponding to data tobe written on the recording medium; and a pole layer that incorporates atrack width defining portion having an end face located in the mediumfacing surface, the pole layer allowing a magnetic flux corresponding tothe field generated by the coil to pass therethrough and generating awrite magnetic field for writing the data on the recording medium, thesubstructure comprising: a substrate; a plurality of sets of the polelayer and the coil formed in the substrate, such that a plurality ofrows of pre-head portions that will be the respective magnetic headslater are aligned; and a plurality of indicators each of which serves asa reference for indicating a region in which the medium facing surfacesof the magnetic heads are to be formed.
 26. The substructure accordingto claim 25, wherein: the end face of the track width defining portionlocated in the medium facing surface has: a first side close to thesubstrate; a second side located opposite to the first side; a thirdside connecting an end of the first side to an end of the second side;and a fourth side connecting the other end of the first side to theother end of the second side; the second side defines a track width; andthe end face of the track width defining portion has a width thatdecreases as a distance from the first side decreases.
 27. Thesubstructure according to claim 25, wherein the indicators are providedon both sides of the track width defining portion, the sides beingopposed to each other in a direction of width of the defining portion.28. The substructure according to claim 27, wherein each of the polelayers and the indicators is conductive, and the indicators areelectrically connected to the respective pole layers.
 29. Thesubstructure according to claim 25, further comprising an encasing layerhaving grooves that accommodate the pole layers.
 30. The substructureaccording to claim 29, wherein the indicators are made of a layerlocated at a height the same as a height at which the pole layers arelocated.
 31. The substructure according to claim 25, further comprisinga magnetic layer having portions that will be the pole layers; and theindicators are made up of other portions of the magnetic layer.
 32. Thesubstructure according to claim 31, further comprising an encasing layerhaving a groove that accommodates the magnetic layer.
 33. Thesubstructure according to claim 25, further comprising a magnetic layerhaving portions that will be the pole layers, wherein the indicators aremade up of a layer other than the magnetic layer.
 34. The substructureaccording to claim 33, further comprising an encasing layer having afirst groove that accommodates the magnetic layer and second groovesthat accommodate the indicators.
 35. The substructure according to claim25, wherein the indicators are made of a layer located closer to thesubstrate than the pole layers.
 36. The substructure according to claim25, wherein the indicators are made of a layer having conductivity. 37.The substructure according to claim 25, further comprising an encasinglayer having grooves that accommodate the pole layers and other groovesthat form the indicators.
 38. The substructure according to claim 25,wherein each of the indicators have an end that is parallel to theregion in which the medium facing surfaces are to be formed, and alocation of the end serves as a reference for indicating a location ofthe region.
 39. The substructure according to claim 38, wherein adistance between a location of the reference and the region falls withina range of 0 to 1.0 μm inclusive.
 40. The substructure according toclaim 25, wherein each of the indicators have two ends that are parallelto the region in which the medium facing surfaces are to be formed, anda location of a middle between the two ends serves as a reference forindicating a location of the region.
 41. The substructure according toclaim 40, wherein a distance between a location of the reference and theregion falls within a range of 0 to 1.0 μm inclusive.
 42. Thesubstructure according to claim 25, wherein a distance between the trackwidth defining portion and the indicators taken in a direction of widthof the defining portion falls within a range of 0.1 to 5.0 μm inclusive.43. The substructure according to claim 25, wherein the indicators arelocated in a region that will not remain in the magnetic heads.
 44. Thesubstructure according to claim 25, wherein at least part of each of theindicators is located in a region that will remain in the magneticheads.
 45. The substructure according to claim 44, wherein the part ofeach of the indicators that remains in the magnetic heads indicates alength of the track width defining portion taken in a directionorthogonal to the medium facing surface.
 46. The substructure accordingto claim 25, wherein the magnetic heads are those used for aperpendicular magnetic recording system.